CA1289318C - Molding process of fiber reinforced plastics - Google Patents
Molding process of fiber reinforced plasticsInfo
- Publication number
- CA1289318C CA1289318C CA000554779A CA554779A CA1289318C CA 1289318 C CA1289318 C CA 1289318C CA 000554779 A CA000554779 A CA 000554779A CA 554779 A CA554779 A CA 554779A CA 1289318 C CA1289318 C CA 1289318C
- Authority
- CA
- Canada
- Prior art keywords
- mold
- resin
- edges
- resins
- pinch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/32—Component parts, details or accessories; Auxiliary operations
- B29C43/36—Moulds for making articles of definite length, i.e. discrete articles
- B29C43/40—Moulds for making articles of definite length, i.e. discrete articles with means for cutting the article
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/32—Component parts, details or accessories; Auxiliary operations
- B29C43/36—Moulds for making articles of definite length, i.e. discrete articles
- B29C43/3607—Moulds for making articles of definite length, i.e. discrete articles with sealing means or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14778—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the article consisting of a material with particular properties, e.g. porous, brittle
- B29C45/14786—Fibrous material or fibre containing material, e.g. fibre mats or fibre reinforced material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/40—Shaping or impregnating by compression not applied
- B29C70/42—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles
- B29C70/46—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
- B29C70/467—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs and impregnating the reinforcements during mould closing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2077/00—Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/24—Condition, form or state of moulded material or of the material to be shaped crosslinked or vulcanised
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2277/00—Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as reinforcement
Abstract
ABSTRACTS
A molding process of fiber reinforced plastics which comprises:
placing fiber reinforcements on a half of a mold which has positive pinch-off edges;
positioning the mold halves near to each other to grasp the fibers between the pinch-off edges:
injecting a resin into a mold cavity through a resin injection opening provided in the mold; and closing the mold This process permits the use of low viscosity resins without the escape of the resin from the mold during the impregnation of fiber reinforcements in the mold cavity, so that the process can readily produce in practical manners fiber reinforced plastics with high fiber contents as much as about 50-80 % by weight that have not been achieved by the conventional resin injection and mat or preform matched die molding processes.
A molding process of fiber reinforced plastics which comprises:
placing fiber reinforcements on a half of a mold which has positive pinch-off edges;
positioning the mold halves near to each other to grasp the fibers between the pinch-off edges:
injecting a resin into a mold cavity through a resin injection opening provided in the mold; and closing the mold This process permits the use of low viscosity resins without the escape of the resin from the mold during the impregnation of fiber reinforcements in the mold cavity, so that the process can readily produce in practical manners fiber reinforced plastics with high fiber contents as much as about 50-80 % by weight that have not been achieved by the conventional resin injection and mat or preform matched die molding processes.
Description
A Molding Process of Fiber Reinf rced Plastics This invention relates to a molding process of fiber reinforced plastics which is capable of producing at high production rates fiber reinforced plastics having larger contents of reinforcing fibers and thus having an enhanced lS mechanical strength than the conventional fiber reinforced plastics.
Plash molds are generally used in resin injection molding or resin transfer molding process. In this molding process, reinforcing fibers are first placed on a half of a mold having elastic packings on the mating surfaces, the mold is closed or clamped, a resin is injected into a mold cavity through a resin injection opening under a pressure to impregnate or wet the fibers therewith, and the resin is cured, thereby to provide fiber reinforced plastics.
In this molding process, the reinforcing fibers are first placed in a mold cavity, and after the mold is closed, a resin is injected into the mold cavity. Therefore, the resin must be injected into a mold cavity under a large pressure even when the resin has a low viscosity, and the larger the fiber contents in the resultant composites, the larger the pressures needed. Ilowever, even when low viscosity resins are used, it is difficult to distribute the resin equally throughout the entire fibers in the mold cavity since the mold is closed.
As is well known in the art, therefore, when, for . ~ , .
:- :
?o18 example, unsaturated polyester resins reinforced with glass fiber chopped strand mats as fiber reinforcements are molded by use of fiber reinforced resin molds, the fiber content is usually about 30 % by weight at most. Even when a combination of glass roving cloths and chopped strand mats is used, the fiber content is usually in the range of about 40-45 % by weight at most. If there be used molds with a higher strength and resin injection apparatus with a larger injection pressure, fiber reinforced plastics having a higher fiber content would be obtainable from the theoretical standpoint. However, no such processes have heretofore been put to practical use because of technical and economical problems involved. The higher the fiber contents in fiber reinforced plastics, the greater the mechanical strength of the composites, however, the conventional resin injection molding process has failed to incorporate fiber reinforcements into composites to the allowable limits.
On the other hand, mat or preform matched die molding process uses mats or preforms which have been preliminarily prepared with reinforcing fibers so as roughly to have forms of final products. In this process the mat or preform is first placed on a mold half, a resin is spread on the mat or preform, and then the preheated mold is closed so that the resin cures. This process has also a disadvantage in that when a low viscosity resin is spread on mats or preforms deposited on a core, the resin escapes from the mold before the mold is closed. Therefore, the process usually uses such resins as mixed with additives and having an increased viscosity. However, this makes difficult to produce fiber reinforced plastics having high fiber contents compared with the processes where low viscosity resins are used. Further-more, fiber reinforced plastic composites produced by the - mat or preform matched die molding process contain fibers usually in amounts of about 30 % by weight at most when glass fiber chopped strand mats are used as fiber reinforcements.
The mat or preform matched die molding process has a further disadvantage from the environmental standpoint in that resins are scattered around molding equipments and give out a bad smell, in contrast to processes in which resins are injected into a closed mold cavity.
As set forth above, the conventional resin injection molding and mat or preform matched die molding processes are not suitable for the production of fiber reinforced plastics with fiber content and strength increased to the allowable limits at high production rates.
The present inventors have made extensive investigations to establish a process which enables the production of fiber reinforced plastics which have increased fiber contents and enhanced mechanical strength with a high productivity by combining the conventional resin injection moldlng and mat or preform matched die molding processes together into a new integrated process in which the use of a mold which has positive pinch-off edges provided thereon is essentially important.
It is, therefore, an object of the invention to provide a molding process for forming an article of fiber reinforced plastics, particularly a molding process which enables the production of an article made of fiber reinforced plastics with high flber contents and hence high mechanical strength at high production rates which the conventional molding processes have failed to achieve.
The molding process for producing an article of fiber reinforced plastics of the invention comprises:
1.8 3a 27571-14 placing flber reinforcemen~s on a lower half of a mold which has two mold halves defining a mold cavity and which has positive pinch-off edges, the amount of the fiber reinforcements being about 50 to about 80% by weight based on the resulting fiber reinforced plastics;
positioning the mold halves near to each other but yet not, completely closing the mold to grasp the fibers between the pinch-off edges so that resin does not escape from the mold through the fiber reinforcements when resin is injected into the mold cavity and distributed thereln;
ln~ecting a resin which has a viscosity of not more than about 1500 cups into the mold cavity through a resin injection opening provided in the mold, ~hereby enabling ready and thorough impregnation of the fiber reinforcements; and closing the mold and thereby applying a mold pressure to form the article.
Features and advantages of . .
the ;nvent;on will appear more fully from the following description taken in connection with the accomPanYing drawings, wherein:
Fig. 1 is a sectiona] view of an example of a mold S used in the process of the invention;
Fig. 2 is an enlarged sectional view of engaging positive pinch-off edges formed on the mold;
Fig. 3 is also an enlarged sectional view of another type of pinch-off edges;
Fig. 4 il]ustrates two halves of a mold positioned near to each other to grasp the reinforcing fibers between the pinch-off edges; and Fig. 5 is an enlarged sectional view of an example of unengaging pinch-off edges.
Referring first to Fig. 1, there is shown a sectional view of an example of a mold 11 used in the invention, which includes a core 12 and a cavity 13 having a resin injection opening 14 therethrough. In the figure, the mold is closed between mold platens 15 and 16 operated by a hydraulic press (not shown). The mold has positive pinch-off ed8es. Fig. 2 is an enlarged sectionai view of an example of such positive pinch-off edges 17 under engagement with a clearance there-between, The pinch-off edges are formed by cooperation of surface portions 18 including an edge on the core 12 and surface portions 19 including an edge of the cavity 13 of the mold.
Molds used in matched die molding procesess are provided with such positive pinch-off edges, and such molds are usable in the process of the invention. The travel of the pinch-off edges depends upon the volume of fiber reinforcements deposited in a mold, however, it is usually in the range of about 2-30 mm, preferably in the range of about 3-lQ mm. The clearance between the pinch-off edges is preferably in the range of about 0.05-0.15 mm.
Fig. 3 shows an enlarged sectional view of another type 27571_14 of pinch-off ed~es 17, and the cavi~y 13 has a pinch off ed~e with a blade 20 al the end.
According to the process of the invention, when resins are injected into a mold cavity 21 and distributed therein, the mold halves are positioned near to each other, as illustrated in Fig. 4, so lhat the pinch-off edges 17 grasp the fibers 22 therebetween to prevent the escape of the resins from the mold 11 througll lhe fibers The mold may be of metals or resins, and the former is preferred when fiber reinforced plastics are mass-produced.
The shape of molds used is designed in accordance with the shape of final products.
Piber reinforcements usable in the invention include those wllich are used in lhe produclion of ordinary fiber reinforced plastics, and such fibers are exemplified by inorganic or melal fibers sucll as glass libers, carbon fibers, quartz fibe~s, ceramic fibers, ~irconia fibers, boron fibers, lungsten fibers, molybdenum fibers, steel fibers, beryllium fibers or stainless steel fibers, and synlhetic fibers such as polyamide fibers or polycster fibers. The fiber rein-forcements may be treated with a coupling a~ent to impro~e adhesion lo resins.
Further. the fibers may be used alone or in combination of two or more of the above, and may be in the form either of preforms, mats or clolhs, or a combination of these forms.
In the process of the invention, the fiber content in fih~r rein~orced plastics depend upon the viscosi-ty of the resin used, fiber reinforcements and their forms, and re4uisites to final producls needed, and is usually in the range of about 50-S0% by weight, preferably in the range of about 50 70 D~ by weight based on the fiber reinforced plastics.
According to the process of the invention, reinforcin~
fibers are first deposited on a lower half of a mold, and lhen the mold haves are brought near to each other and are ~ositioned to grasp or calch hold of tlle fibers between lhe .
.: .
~ 8 pinch-off edges so that the resins do not escape from the mold when the resins are injected onto the fibers in a mold cavity. In the process of the invention, as a means to drive the mold, a hydraulic press is usable which is normallY used in compression molding of fiber reinforced plastics. It is preferred that the hydraulic press has position control attachments to first position the mold halves near to each other, and then to drive and close the mold.
It is essential in the process of the invention that the mold halves are positioned so that the pinch-off edges grasp therebetween the fibers in the mold, not allowing resins to escape from between the pinch-off edges when the resins are injected into a mold cavity to impregnate the fibers therein.
~ig. 5 illustrates a preferred position of pinch-off edges 17 to grasp fiber reinforcement therebetween. The pinch-off edges have a distance D between the edge of a core 12 and the edge of a cavity 13 of a mold. The distance D is selected depending upon the volume or thickness of fiber reinforcements 22 deposited on a core 12, but is usually in the range of about 0-5 mm. The fiber reinforcements in a mold cavity 21 extends beyond the pinch-off edges 17 and are grasped therebetween at the end portions. This position is preferred since resins are readily injected into a mold cavity under a low pressure while the escape of the resins through the fiber reinforcements is prevented at the pinch-off edges. The fiber reinforcements are generally voluminous, and especially glass fiber reinforcements are the case, so that it is not necessary to grasp the fiber reinforcements firmly between the pinch-off edges if the escape of the resins is prevented at the pinch-off edges.
However, the pinch-off edges may be either slightly or deeply engaged with each other (depending upon the volume or thickness of fiber reinforcements on a core~ over a distance usually of about U-l mm, to cut off the fiber reinforcements .8 extending beyond the mold provided that the mold has not been completely closed, as shown in Figs. 2 and 3.
Then resins are injected onto the fibers in a cavity under a pressure usually of several kg/cm2. ~ny means may be utilized for the resin injection, such as pumps or normal injector used in reaction injection molding process.
The process of the invention is applicable to any resin which is usable in the production of ordinary fiber rein-forced plastics. However, thermosetting resins are preferred, such as unsaturated polyester resins, vinyl ester resins, epoxy resins, polYurethane resins, polyimide resins, phenol resins, silicone resins, cross-linkable polyesteramide resins, cross-linkable polyaminoamide resins, cross-linkable epoxy-modified polyaminoamide resins or cross-linkable polyether-amide resins.
The unsaturated polyester resins are, as well known, aliquid mixture of unsaturated alkyds and vinyl monomers. The unsaturated alkyds are obtained by polycondensation of poly-basic carboxylic acids such as phthalic anhydride, isophthalic acid, maleic anhydride or fumaric acid, with glycols such as ethylene glycol or propylene glycol, whereas the vinyl monomers are exemplified by styrene, The unsaturated polyester resins are superior in moldability, and widely used as matrices of fiber reinforced plastics. Epoxy resins and epoxy modified vinyl ester resins are superior to the unsaturated polyester resins since the former two resins have higher mechanical strength and smaller cure shrinkage than the unsaturated polyester resins are also widely used as matrices. Most of the epoxy resins used are fast curable bisphenol A type epoxy resins, Polyurethane resins produced by the reaction of polyisocyanates and polyols are also rapidly curable and are one of the preferred matrices.
One of the most preferred cross-linkable resins used in the process of the invention is cross-linkable polyamide resins such as polyesteramide resins obtained by the reaction ~ 8 of 2,2'-(1,3-phenylene)bis-2-oxazoline with reactants such as dibasic carboxylic acids, aromatic hydroxy carboxylic acid, carboxylic acid anhydrides, e.g., adipic acid, sebacic acid, phthalic acid, salicylic acid, p-hydroxybenzoic acid or phthalic anhydride, or a mixture of two or more, preferably in the presence of catalysts SUCtl as phosphorous acid, as disclosed in U.S. Patent No. 4,474,942, No, 4,579,937 and No. 4,600,766. The cross-linkable polyamide resins usable in the invention further include polyaminoamide resins obtained by the reaction of 2,2'-(1,3-phenylene)-bis-2-oxazoline with diamine compounds such as diaminodiphenylmethane in the presence of catalysts, epoxy modified cross-linkable poly-aminoamide resins obtained by the reaction of 2,2'-(1.3-phenylene)-bis-2-oxazoline with diamine compounds and epoxy resins, and polyetheramide resins obtained by the reaction of 2,2'-(1,3-phenylene)bis-2-oxazoline with phenolic compounds or polymers.
In the process of the invention, the resins may be used either as one-component, two-component or three-component systems. When used as one-component systems, a mixture of base resins and curing agents are prepared in a tank, and the mixture is injected into a mold cavity. When used as two-component or three-component systems, base resins and curing agents are separately stored in tanks and injected into a mold cavity through a mixing means.
The resins may contain catalysts, stabilizers, parting agents, colorants, fire-retardants or fillers depending upon the resins used and requisites to the resultant fiber rein-forced plastics. The process of the invention is suitable for high rate production of fiber reinforced plastics by use of fast curable resins. Further, when fiber reinforced plastics with high fiber contents are to be produced, it is desired to use resins which have a relatively low viscosity of not more than about 1500 cps (centipoise) when being iniected into a mold cavity so that the fibers are readily wetted and impregnated therewith.
It is especially desired that resins are as low in viscosity as not more than about 1000 cps, and most preferably the resins have a viscosity of about of 10-300 cps at tempera-tures at which the resins are injected into a mold cavity toobtain fiber reinforced plastics with fiber contents as much as about 50-80 ~ by weight based on the fiber reinforced plastics, It is also desired, however, that the resins used generate no cracks during curing if the resins contain no fillers so that they have a low viscosity.
According to the process of the invention, the mold is closed by driving a mold half by means of a hydraulic press while the other half is fixed after the resins have been injected into a mold cavity. No heating is necessary when thermoplastic resins are used, but when cross-linkable resins are used, the mold is preheated usually at temperatures of about 100-250c. The molding pressures are usually in the range of about 10-50 kg/cmZ, and the cycle times are usually in the range of about 30 seconds to about 30 minutes, although the molding pressures and cycle times being not critical and varying depending upon the resins, catalysts or fiber reinforcements used, or thickness of the resultant composites.
As set forth above, according to the invention, rein-forcing fibers are first deposited in a mold, the mold halves are positioned near to each other to grasp the fibers between the pinch-off edges, and then resins are injected into a mold cavity while the mold cavity still has a wide space since the mold has not yet been closed completely. Therefore, the resins can be injected into the mold under a very low pressure, while no escape of the resins from the mold takes place if low viscosity resins are used, since the fibers are grasped between the pinch-off edges of the mold to prevent the escape of the resins from the mold through the fibers.
This use of such low viscosity resins enables ready and thorough impregnation of the fiber reinforcements with ?~.8 the resins under low pressures, so that the process of the invention can readily produce in practical manners fiber reinforced plastics with high fiber contents as much as about 50-80 ~ by weight that have not been achieved by the conven-tional resin injection and mat or preform matched die fiberreinforced plastics molding processes. As a further aspect, the process of the invention is superior to the conventional molding processes such as the mat or preform matched die molding process from environmental standpoint in that there arises substantially no problem of resin scattering or bad smell.
Furthermore, the use of low viscosity resins permits the use of much smaller capacity hydraulic presses in this molding process than in the compression molding Process wherein sheet molding compounds or bulk molding compounds are molded.
In this way, fiber reinforced plastics with much higher fiber contents and much higher mechanical strengths are readily produceable with high production rates according to the process of the invention than in the conventional resin injection molding and mat or preform matched die molding processes.
The invention will be understood more readily in refe-rence to the following examples, however, these examples are intended to illustrate the invention only, and are not to be construed as limitings to the invention.
Example Using cross-linkable polyesteramide resins and glass fibers, fiber reinforced plastic trays were produced in a testing mold having pinch-off edges as shown in Figs. 1 and 2 provided with a resin injector used in reaction injection molding and an up-stroke hydraulic press to drive the lower half of the mold.
Preparation of Resins An amount of 8.25 kg of 2,2'-(1,3-Phenylene)bis-2 ~ . ~
~It~ 8 oxazoline, 1.11 kg of p-hydroxybenzoic acid and 0.64 kg of salicylic acid were weighed respectively and dry blended with each other. The mixture was placed in a tank A heated at about 150 c and stirred to form a melted liquid.
An amount of 2.6 kg of 2,2'-(1,3-PhenYIene)bis-2-oxazoline, 1.85 kg of salicylic acid, 5.55 kg of sebacic acid and 0. 75 kg of phosphorous acid were weighed respectively, and dry blended together. The mixture was placed in a tank B heated at about 150c and stirred to form a melted liquids.
Then the temperature of both the liquids was adiusted to 140 c . The liquids in the tank A and B were found about 40 cps and about 50 cps at 140C, respectively, by Brookfield type viscometers. The mixing ratio of the liquid A to B was 15 adjusted to 80/21.5 in weight, and the discharge amount to 123 g/sec, with discharge pressures of A and B about 70 kg/cmZ
and about 140 kg/cm2, respectively.
Molds and Hydraulic Presses Used The mold used had pinch-off edges with a travel of 5 mm 20 and a clearance therebetween of 0.1 mm, as shown in Fig. 2, and a mold cavity of 40 cm in length, 27 cm in width, 2 cm in depth and 3 mm in thickness. A mixing head of a resin injector used in reaction injection molding was mounted on the top half of the mold to inject the resin into the mold 25 cavity.
The mold was heated with electric heaters inserted thereinto so that the surface of the mold had a temperature of 200 c . Then the mold was opened, and a parting agent, wax, was coated on the surface of the mold.
Molding Continuous strand mats (M 8609 by Asahi Fiber Glass K.K., Japan, 450 g/mZ, about 47 cm in length and about 34 cm in width) were deposited in eight layers on the core of the mold, and then the lower half of the mold was moved upwards so that 35 the pinch-off edges had a distance D of about 2 mm there-sl~
between, as shown in Fig. 5.
The resin injector was operated for 2.2 seconds to inject the resin into the mold through an impingement mixing means. The calculated discharge amount was 270 g. Immediately after the injection, the lower half of the mold was moved upwards at a rate of about 0.5 mm/sec until the mold halves came into contact with each other at spacers on the lands, and thus the mold was completely closed.
~fter two minute heating under a pressure of about 30 kg/cm2, the mold was opened and the resultant tray was taken out of the mold. The tray was found 2~84 mm in average thick-ness. The tray was cut into test pieces and the properties were measured according to JIS methods. The results are shown in Table 1.
Example 2 The same continuous strand mats as in Example 1 were placed in ten layers, and otherwise in the same manner as in Example 1. fiber reinforced plastic trays were produced. The 20 properties are shown in Table 1.
Example 3 In place of the continuous strand mats as used in Example 1, there were used glass fiber reinforcements composed of two layers of unidirectional glass roving cloth (REW 650X-HM by Nippon Glass Sen-i K.K., Japan) as both of the surface layers, and the same continuous strand mats as used in Example 1 in three layers as middle layers, and otherwise in the same manner as in Example 1, fiber reinforced plastic trays were produced.
The properties are shown in Table l.
.8 O O ~
Plash molds are generally used in resin injection molding or resin transfer molding process. In this molding process, reinforcing fibers are first placed on a half of a mold having elastic packings on the mating surfaces, the mold is closed or clamped, a resin is injected into a mold cavity through a resin injection opening under a pressure to impregnate or wet the fibers therewith, and the resin is cured, thereby to provide fiber reinforced plastics.
In this molding process, the reinforcing fibers are first placed in a mold cavity, and after the mold is closed, a resin is injected into the mold cavity. Therefore, the resin must be injected into a mold cavity under a large pressure even when the resin has a low viscosity, and the larger the fiber contents in the resultant composites, the larger the pressures needed. Ilowever, even when low viscosity resins are used, it is difficult to distribute the resin equally throughout the entire fibers in the mold cavity since the mold is closed.
As is well known in the art, therefore, when, for . ~ , .
:- :
?o18 example, unsaturated polyester resins reinforced with glass fiber chopped strand mats as fiber reinforcements are molded by use of fiber reinforced resin molds, the fiber content is usually about 30 % by weight at most. Even when a combination of glass roving cloths and chopped strand mats is used, the fiber content is usually in the range of about 40-45 % by weight at most. If there be used molds with a higher strength and resin injection apparatus with a larger injection pressure, fiber reinforced plastics having a higher fiber content would be obtainable from the theoretical standpoint. However, no such processes have heretofore been put to practical use because of technical and economical problems involved. The higher the fiber contents in fiber reinforced plastics, the greater the mechanical strength of the composites, however, the conventional resin injection molding process has failed to incorporate fiber reinforcements into composites to the allowable limits.
On the other hand, mat or preform matched die molding process uses mats or preforms which have been preliminarily prepared with reinforcing fibers so as roughly to have forms of final products. In this process the mat or preform is first placed on a mold half, a resin is spread on the mat or preform, and then the preheated mold is closed so that the resin cures. This process has also a disadvantage in that when a low viscosity resin is spread on mats or preforms deposited on a core, the resin escapes from the mold before the mold is closed. Therefore, the process usually uses such resins as mixed with additives and having an increased viscosity. However, this makes difficult to produce fiber reinforced plastics having high fiber contents compared with the processes where low viscosity resins are used. Further-more, fiber reinforced plastic composites produced by the - mat or preform matched die molding process contain fibers usually in amounts of about 30 % by weight at most when glass fiber chopped strand mats are used as fiber reinforcements.
The mat or preform matched die molding process has a further disadvantage from the environmental standpoint in that resins are scattered around molding equipments and give out a bad smell, in contrast to processes in which resins are injected into a closed mold cavity.
As set forth above, the conventional resin injection molding and mat or preform matched die molding processes are not suitable for the production of fiber reinforced plastics with fiber content and strength increased to the allowable limits at high production rates.
The present inventors have made extensive investigations to establish a process which enables the production of fiber reinforced plastics which have increased fiber contents and enhanced mechanical strength with a high productivity by combining the conventional resin injection moldlng and mat or preform matched die molding processes together into a new integrated process in which the use of a mold which has positive pinch-off edges provided thereon is essentially important.
It is, therefore, an object of the invention to provide a molding process for forming an article of fiber reinforced plastics, particularly a molding process which enables the production of an article made of fiber reinforced plastics with high flber contents and hence high mechanical strength at high production rates which the conventional molding processes have failed to achieve.
The molding process for producing an article of fiber reinforced plastics of the invention comprises:
1.8 3a 27571-14 placing flber reinforcemen~s on a lower half of a mold which has two mold halves defining a mold cavity and which has positive pinch-off edges, the amount of the fiber reinforcements being about 50 to about 80% by weight based on the resulting fiber reinforced plastics;
positioning the mold halves near to each other but yet not, completely closing the mold to grasp the fibers between the pinch-off edges so that resin does not escape from the mold through the fiber reinforcements when resin is injected into the mold cavity and distributed thereln;
ln~ecting a resin which has a viscosity of not more than about 1500 cups into the mold cavity through a resin injection opening provided in the mold, ~hereby enabling ready and thorough impregnation of the fiber reinforcements; and closing the mold and thereby applying a mold pressure to form the article.
Features and advantages of . .
the ;nvent;on will appear more fully from the following description taken in connection with the accomPanYing drawings, wherein:
Fig. 1 is a sectiona] view of an example of a mold S used in the process of the invention;
Fig. 2 is an enlarged sectional view of engaging positive pinch-off edges formed on the mold;
Fig. 3 is also an enlarged sectional view of another type of pinch-off edges;
Fig. 4 il]ustrates two halves of a mold positioned near to each other to grasp the reinforcing fibers between the pinch-off edges; and Fig. 5 is an enlarged sectional view of an example of unengaging pinch-off edges.
Referring first to Fig. 1, there is shown a sectional view of an example of a mold 11 used in the invention, which includes a core 12 and a cavity 13 having a resin injection opening 14 therethrough. In the figure, the mold is closed between mold platens 15 and 16 operated by a hydraulic press (not shown). The mold has positive pinch-off ed8es. Fig. 2 is an enlarged sectionai view of an example of such positive pinch-off edges 17 under engagement with a clearance there-between, The pinch-off edges are formed by cooperation of surface portions 18 including an edge on the core 12 and surface portions 19 including an edge of the cavity 13 of the mold.
Molds used in matched die molding procesess are provided with such positive pinch-off edges, and such molds are usable in the process of the invention. The travel of the pinch-off edges depends upon the volume of fiber reinforcements deposited in a mold, however, it is usually in the range of about 2-30 mm, preferably in the range of about 3-lQ mm. The clearance between the pinch-off edges is preferably in the range of about 0.05-0.15 mm.
Fig. 3 shows an enlarged sectional view of another type 27571_14 of pinch-off ed~es 17, and the cavi~y 13 has a pinch off ed~e with a blade 20 al the end.
According to the process of the invention, when resins are injected into a mold cavity 21 and distributed therein, the mold halves are positioned near to each other, as illustrated in Fig. 4, so lhat the pinch-off edges 17 grasp the fibers 22 therebetween to prevent the escape of the resins from the mold 11 througll lhe fibers The mold may be of metals or resins, and the former is preferred when fiber reinforced plastics are mass-produced.
The shape of molds used is designed in accordance with the shape of final products.
Piber reinforcements usable in the invention include those wllich are used in lhe produclion of ordinary fiber reinforced plastics, and such fibers are exemplified by inorganic or melal fibers sucll as glass libers, carbon fibers, quartz fibe~s, ceramic fibers, ~irconia fibers, boron fibers, lungsten fibers, molybdenum fibers, steel fibers, beryllium fibers or stainless steel fibers, and synlhetic fibers such as polyamide fibers or polycster fibers. The fiber rein-forcements may be treated with a coupling a~ent to impro~e adhesion lo resins.
Further. the fibers may be used alone or in combination of two or more of the above, and may be in the form either of preforms, mats or clolhs, or a combination of these forms.
In the process of the invention, the fiber content in fih~r rein~orced plastics depend upon the viscosi-ty of the resin used, fiber reinforcements and their forms, and re4uisites to final producls needed, and is usually in the range of about 50-S0% by weight, preferably in the range of about 50 70 D~ by weight based on the fiber reinforced plastics.
According to the process of the invention, reinforcin~
fibers are first deposited on a lower half of a mold, and lhen the mold haves are brought near to each other and are ~ositioned to grasp or calch hold of tlle fibers between lhe .
.: .
~ 8 pinch-off edges so that the resins do not escape from the mold when the resins are injected onto the fibers in a mold cavity. In the process of the invention, as a means to drive the mold, a hydraulic press is usable which is normallY used in compression molding of fiber reinforced plastics. It is preferred that the hydraulic press has position control attachments to first position the mold halves near to each other, and then to drive and close the mold.
It is essential in the process of the invention that the mold halves are positioned so that the pinch-off edges grasp therebetween the fibers in the mold, not allowing resins to escape from between the pinch-off edges when the resins are injected into a mold cavity to impregnate the fibers therein.
~ig. 5 illustrates a preferred position of pinch-off edges 17 to grasp fiber reinforcement therebetween. The pinch-off edges have a distance D between the edge of a core 12 and the edge of a cavity 13 of a mold. The distance D is selected depending upon the volume or thickness of fiber reinforcements 22 deposited on a core 12, but is usually in the range of about 0-5 mm. The fiber reinforcements in a mold cavity 21 extends beyond the pinch-off edges 17 and are grasped therebetween at the end portions. This position is preferred since resins are readily injected into a mold cavity under a low pressure while the escape of the resins through the fiber reinforcements is prevented at the pinch-off edges. The fiber reinforcements are generally voluminous, and especially glass fiber reinforcements are the case, so that it is not necessary to grasp the fiber reinforcements firmly between the pinch-off edges if the escape of the resins is prevented at the pinch-off edges.
However, the pinch-off edges may be either slightly or deeply engaged with each other (depending upon the volume or thickness of fiber reinforcements on a core~ over a distance usually of about U-l mm, to cut off the fiber reinforcements .8 extending beyond the mold provided that the mold has not been completely closed, as shown in Figs. 2 and 3.
Then resins are injected onto the fibers in a cavity under a pressure usually of several kg/cm2. ~ny means may be utilized for the resin injection, such as pumps or normal injector used in reaction injection molding process.
The process of the invention is applicable to any resin which is usable in the production of ordinary fiber rein-forced plastics. However, thermosetting resins are preferred, such as unsaturated polyester resins, vinyl ester resins, epoxy resins, polYurethane resins, polyimide resins, phenol resins, silicone resins, cross-linkable polyesteramide resins, cross-linkable polyaminoamide resins, cross-linkable epoxy-modified polyaminoamide resins or cross-linkable polyether-amide resins.
The unsaturated polyester resins are, as well known, aliquid mixture of unsaturated alkyds and vinyl monomers. The unsaturated alkyds are obtained by polycondensation of poly-basic carboxylic acids such as phthalic anhydride, isophthalic acid, maleic anhydride or fumaric acid, with glycols such as ethylene glycol or propylene glycol, whereas the vinyl monomers are exemplified by styrene, The unsaturated polyester resins are superior in moldability, and widely used as matrices of fiber reinforced plastics. Epoxy resins and epoxy modified vinyl ester resins are superior to the unsaturated polyester resins since the former two resins have higher mechanical strength and smaller cure shrinkage than the unsaturated polyester resins are also widely used as matrices. Most of the epoxy resins used are fast curable bisphenol A type epoxy resins, Polyurethane resins produced by the reaction of polyisocyanates and polyols are also rapidly curable and are one of the preferred matrices.
One of the most preferred cross-linkable resins used in the process of the invention is cross-linkable polyamide resins such as polyesteramide resins obtained by the reaction ~ 8 of 2,2'-(1,3-phenylene)bis-2-oxazoline with reactants such as dibasic carboxylic acids, aromatic hydroxy carboxylic acid, carboxylic acid anhydrides, e.g., adipic acid, sebacic acid, phthalic acid, salicylic acid, p-hydroxybenzoic acid or phthalic anhydride, or a mixture of two or more, preferably in the presence of catalysts SUCtl as phosphorous acid, as disclosed in U.S. Patent No. 4,474,942, No, 4,579,937 and No. 4,600,766. The cross-linkable polyamide resins usable in the invention further include polyaminoamide resins obtained by the reaction of 2,2'-(1,3-phenylene)-bis-2-oxazoline with diamine compounds such as diaminodiphenylmethane in the presence of catalysts, epoxy modified cross-linkable poly-aminoamide resins obtained by the reaction of 2,2'-(1.3-phenylene)-bis-2-oxazoline with diamine compounds and epoxy resins, and polyetheramide resins obtained by the reaction of 2,2'-(1,3-phenylene)bis-2-oxazoline with phenolic compounds or polymers.
In the process of the invention, the resins may be used either as one-component, two-component or three-component systems. When used as one-component systems, a mixture of base resins and curing agents are prepared in a tank, and the mixture is injected into a mold cavity. When used as two-component or three-component systems, base resins and curing agents are separately stored in tanks and injected into a mold cavity through a mixing means.
The resins may contain catalysts, stabilizers, parting agents, colorants, fire-retardants or fillers depending upon the resins used and requisites to the resultant fiber rein-forced plastics. The process of the invention is suitable for high rate production of fiber reinforced plastics by use of fast curable resins. Further, when fiber reinforced plastics with high fiber contents are to be produced, it is desired to use resins which have a relatively low viscosity of not more than about 1500 cps (centipoise) when being iniected into a mold cavity so that the fibers are readily wetted and impregnated therewith.
It is especially desired that resins are as low in viscosity as not more than about 1000 cps, and most preferably the resins have a viscosity of about of 10-300 cps at tempera-tures at which the resins are injected into a mold cavity toobtain fiber reinforced plastics with fiber contents as much as about 50-80 ~ by weight based on the fiber reinforced plastics, It is also desired, however, that the resins used generate no cracks during curing if the resins contain no fillers so that they have a low viscosity.
According to the process of the invention, the mold is closed by driving a mold half by means of a hydraulic press while the other half is fixed after the resins have been injected into a mold cavity. No heating is necessary when thermoplastic resins are used, but when cross-linkable resins are used, the mold is preheated usually at temperatures of about 100-250c. The molding pressures are usually in the range of about 10-50 kg/cmZ, and the cycle times are usually in the range of about 30 seconds to about 30 minutes, although the molding pressures and cycle times being not critical and varying depending upon the resins, catalysts or fiber reinforcements used, or thickness of the resultant composites.
As set forth above, according to the invention, rein-forcing fibers are first deposited in a mold, the mold halves are positioned near to each other to grasp the fibers between the pinch-off edges, and then resins are injected into a mold cavity while the mold cavity still has a wide space since the mold has not yet been closed completely. Therefore, the resins can be injected into the mold under a very low pressure, while no escape of the resins from the mold takes place if low viscosity resins are used, since the fibers are grasped between the pinch-off edges of the mold to prevent the escape of the resins from the mold through the fibers.
This use of such low viscosity resins enables ready and thorough impregnation of the fiber reinforcements with ?~.8 the resins under low pressures, so that the process of the invention can readily produce in practical manners fiber reinforced plastics with high fiber contents as much as about 50-80 ~ by weight that have not been achieved by the conven-tional resin injection and mat or preform matched die fiberreinforced plastics molding processes. As a further aspect, the process of the invention is superior to the conventional molding processes such as the mat or preform matched die molding process from environmental standpoint in that there arises substantially no problem of resin scattering or bad smell.
Furthermore, the use of low viscosity resins permits the use of much smaller capacity hydraulic presses in this molding process than in the compression molding Process wherein sheet molding compounds or bulk molding compounds are molded.
In this way, fiber reinforced plastics with much higher fiber contents and much higher mechanical strengths are readily produceable with high production rates according to the process of the invention than in the conventional resin injection molding and mat or preform matched die molding processes.
The invention will be understood more readily in refe-rence to the following examples, however, these examples are intended to illustrate the invention only, and are not to be construed as limitings to the invention.
Example Using cross-linkable polyesteramide resins and glass fibers, fiber reinforced plastic trays were produced in a testing mold having pinch-off edges as shown in Figs. 1 and 2 provided with a resin injector used in reaction injection molding and an up-stroke hydraulic press to drive the lower half of the mold.
Preparation of Resins An amount of 8.25 kg of 2,2'-(1,3-Phenylene)bis-2 ~ . ~
~It~ 8 oxazoline, 1.11 kg of p-hydroxybenzoic acid and 0.64 kg of salicylic acid were weighed respectively and dry blended with each other. The mixture was placed in a tank A heated at about 150 c and stirred to form a melted liquid.
An amount of 2.6 kg of 2,2'-(1,3-PhenYIene)bis-2-oxazoline, 1.85 kg of salicylic acid, 5.55 kg of sebacic acid and 0. 75 kg of phosphorous acid were weighed respectively, and dry blended together. The mixture was placed in a tank B heated at about 150c and stirred to form a melted liquids.
Then the temperature of both the liquids was adiusted to 140 c . The liquids in the tank A and B were found about 40 cps and about 50 cps at 140C, respectively, by Brookfield type viscometers. The mixing ratio of the liquid A to B was 15 adjusted to 80/21.5 in weight, and the discharge amount to 123 g/sec, with discharge pressures of A and B about 70 kg/cmZ
and about 140 kg/cm2, respectively.
Molds and Hydraulic Presses Used The mold used had pinch-off edges with a travel of 5 mm 20 and a clearance therebetween of 0.1 mm, as shown in Fig. 2, and a mold cavity of 40 cm in length, 27 cm in width, 2 cm in depth and 3 mm in thickness. A mixing head of a resin injector used in reaction injection molding was mounted on the top half of the mold to inject the resin into the mold 25 cavity.
The mold was heated with electric heaters inserted thereinto so that the surface of the mold had a temperature of 200 c . Then the mold was opened, and a parting agent, wax, was coated on the surface of the mold.
Molding Continuous strand mats (M 8609 by Asahi Fiber Glass K.K., Japan, 450 g/mZ, about 47 cm in length and about 34 cm in width) were deposited in eight layers on the core of the mold, and then the lower half of the mold was moved upwards so that 35 the pinch-off edges had a distance D of about 2 mm there-sl~
between, as shown in Fig. 5.
The resin injector was operated for 2.2 seconds to inject the resin into the mold through an impingement mixing means. The calculated discharge amount was 270 g. Immediately after the injection, the lower half of the mold was moved upwards at a rate of about 0.5 mm/sec until the mold halves came into contact with each other at spacers on the lands, and thus the mold was completely closed.
~fter two minute heating under a pressure of about 30 kg/cm2, the mold was opened and the resultant tray was taken out of the mold. The tray was found 2~84 mm in average thick-ness. The tray was cut into test pieces and the properties were measured according to JIS methods. The results are shown in Table 1.
Example 2 The same continuous strand mats as in Example 1 were placed in ten layers, and otherwise in the same manner as in Example 1. fiber reinforced plastic trays were produced. The 20 properties are shown in Table 1.
Example 3 In place of the continuous strand mats as used in Example 1, there were used glass fiber reinforcements composed of two layers of unidirectional glass roving cloth (REW 650X-HM by Nippon Glass Sen-i K.K., Japan) as both of the surface layers, and the same continuous strand mats as used in Example 1 in three layers as middle layers, and otherwise in the same manner as in Example 1, fiber reinforced plastic trays were produced.
The properties are shown in Table l.
.8 O O ~
3 3 (D (~ 3 ~ Cl' X X ~ t~7 (D
C C ,_. ,_.
_ _ ~n to ~ ~~ O
~. ~. ~r ~ 3 O 0 3 C~ O
3 0 c~ ~ '~
~ ~ ~ ~ 3 3 C~ C
O ~ .
~ ~ C O~
C ~D cn ~ 5 _ ~ 5 , ~ Oa 0 ~ ~ 3 0~ ~ 3 ~ 3 3 'a 3 3 N 3 3 ~ -- N `--3 3 `_ _ N
_ 1 5 c~
,~ ~ ~ ~3 C~ -~ _3 ~
(D ~ C~' x :~: ~ ~ ~n _.
:~r ~ ~D
~ ~ , o . .
o o o o ,-- ,-- o C~ .
c~ cn c~ ,_ ,~
a~ ~ ~o cn ~ o ~ o ~ cr~
c. o o ~ ~ cn ,~ O ~
~o ~o x~
, , ~o cn cn ~ --~ D~
O O o ~ t`:) 3 . . . 'O
a~
C~
~ C`~ ~ O
co., cn 'o a~ o ~ ~ c~
C~ ~o
C C ,_. ,_.
_ _ ~n to ~ ~~ O
~. ~. ~r ~ 3 O 0 3 C~ O
3 0 c~ ~ '~
~ ~ ~ ~ 3 3 C~ C
O ~ .
~ ~ C O~
C ~D cn ~ 5 _ ~ 5 , ~ Oa 0 ~ ~ 3 0~ ~ 3 ~ 3 3 'a 3 3 N 3 3 ~ -- N `--3 3 `_ _ N
_ 1 5 c~
,~ ~ ~ ~3 C~ -~ _3 ~
(D ~ C~' x :~: ~ ~ ~n _.
:~r ~ ~D
~ ~ , o . .
o o o o ,-- ,-- o C~ .
c~ cn c~ ,_ ,~
a~ ~ ~o cn ~ o ~ o ~ cr~
c. o o ~ ~ cn ,~ O ~
~o ~o x~
, , ~o cn cn ~ --~ D~
O O o ~ t`:) 3 . . . 'O
a~
C~
~ C`~ ~ O
co., cn 'o a~ o ~ ~ c~
C~ ~o
Claims (11)
1. A molding process for forming an article of fiber reinforced plastics, which comprises the following steps in sequence:
placing fiber reinforcements on one half of a mold which has two mold halves defining a mold cavity and which has positive pinch-off edges, the fiber reinforcements being deposited in amounts of about 50-80% by weight based on the resultant fiber reinforced plastics;
positioning the mold halves near to each other yet not completely closing the mold to grasp the fibers between the pinch-off edges so that resin does not escape from the mold through the fiber reinforcements when resin is injected into the mold cavity and distributed therein;
injecting a resin which has a viscosity of not more than about 1500 cps into the mold cavity of the mold halves thus positioned through a resin injection opening provided in the mold, thereby enabling ready and thorough impregnation of the fiber reinforcements; and closing the mold and thereby applying a molding pressure to form the article.
placing fiber reinforcements on one half of a mold which has two mold halves defining a mold cavity and which has positive pinch-off edges, the fiber reinforcements being deposited in amounts of about 50-80% by weight based on the resultant fiber reinforced plastics;
positioning the mold halves near to each other yet not completely closing the mold to grasp the fibers between the pinch-off edges so that resin does not escape from the mold through the fiber reinforcements when resin is injected into the mold cavity and distributed therein;
injecting a resin which has a viscosity of not more than about 1500 cps into the mold cavity of the mold halves thus positioned through a resin injection opening provided in the mold, thereby enabling ready and thorough impregnation of the fiber reinforcements; and closing the mold and thereby applying a molding pressure to form the article.
2. The method as claimed in claim 1 wherein the resin has a viscosity of about 10-300 cps.
3. The method as claimed in claim 1 or 2 wherein the resin is a cross-linkable polyamide resin.
4 The method as claimed in claim 3 wherein the cross-linkable polyamide resin is a cross-linkable polyesteramide resin, a cross-linkable polyaminoamide resin, an epoxy modified cross-linkable polyaminoamide resin or a cross-linkable poly-etheramide resin.
5. The method as claimed in claim 1 or 2 wherein the resin is a cross-linkable polyamide resin obtained by reacting 2,2'-(1,3-phenylene)bis-2-oxazoline with a reactant selected from the group consisting of a dibasic carboxylic acid, an aromatic hydroxy carboxylic acid, a carboxylic acid anhydride and a diamine.
6. A molding process for forming an article of fiber reinforced plastics, which comprises the following steps in sequence:
providing a mold which consists of a lower half, and a top half, and has a resin injection opening and positive pinch-off edges, the lower half and the top half defining a mold cavity;
placing reinforcement fibers on the lower half of the mold in an amount of from about 50 to about 80% by weight based on the resultant fiber reinforced plastics;
positioning the top and lower halves close to each other but not completely closed so that the reinforcement fibers are grasped between the pinch-off edges while the reinforcement fibers beyond the mold are cut off and, when a low viscosity resin having a viscosity of not more than about 1,500 cps is injected into a mold cavity, the resin does not escape from the mold off the reinforcement fibers;
injecting the resin into the mold cavity through the resin injection opening without losing the resin out of the mold;
and completely closing the mold and thereby applying a molding pressure to form the article.
providing a mold which consists of a lower half, and a top half, and has a resin injection opening and positive pinch-off edges, the lower half and the top half defining a mold cavity;
placing reinforcement fibers on the lower half of the mold in an amount of from about 50 to about 80% by weight based on the resultant fiber reinforced plastics;
positioning the top and lower halves close to each other but not completely closed so that the reinforcement fibers are grasped between the pinch-off edges while the reinforcement fibers beyond the mold are cut off and, when a low viscosity resin having a viscosity of not more than about 1,500 cps is injected into a mold cavity, the resin does not escape from the mold off the reinforcement fibers;
injecting the resin into the mold cavity through the resin injection opening without losing the resin out of the mold;
and completely closing the mold and thereby applying a molding pressure to form the article.
7. The method as claimed in claim 6, wherein the resin has a viscosity of 10 to 1,500 cps when being injected into the mold.
8. The method as claimed in claim 7, wherein the resin has a viscosity of about 10 to 300 cps.
9. The method as claimed in claim 6, 7 or 8, wherein a clearance between the pinch-off edges is about 0.05 to 0.15 mm.
10. The method as claimed in claim 6, 7 or 8, wherein the resin is a thermosetting resin and the reinforcement fibers are glass fibers.
11. The method as claimed in claim 10, wherein the resin is a cross-linkable resin and the mold is pre-heated at a temperature of 100 to 250°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP305002/1986 | 1986-12-19 | ||
| JP30500286 | 1986-12-19 |
Publications (1)
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|---|---|
| CA1289318C true CA1289318C (en) | 1991-09-24 |
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ID=17939898
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000554779A Expired - Lifetime CA1289318C (en) | 1986-12-19 | 1987-12-18 | Molding process of fiber reinforced plastics |
Country Status (5)
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|---|---|
| US (1) | US4986948A (en) |
| EP (1) | EP0272635B1 (en) |
| KR (1) | KR950012870B1 (en) |
| CA (1) | CA1289318C (en) |
| DE (1) | DE3780928T2 (en) |
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| GB651192A (en) * | 1946-03-15 | 1951-03-14 | Ernst Altman | Improvements in and relating to recessed articles made from reinforced thermoplasticor thermo-setting type resin |
| US2796634A (en) * | 1953-12-21 | 1957-06-25 | Ibm | Reverse forming process for making shaped articles from plastic sheet material |
| DE1214394B (en) * | 1957-10-01 | 1966-04-14 | Erich M Bayer Dr Ing | Method and device for the production of molded bodies from filling material soaked with synthetic resin |
| US3045284A (en) * | 1958-08-14 | 1962-07-24 | Renault | Closed moulds for initially fluid materials |
| FR1330854A (en) * | 1962-05-16 | 1963-06-28 | Aviation Louis Breguet Sa | Improvements in the manufacture of protective domes for radars and objects of the same kind |
| GB1353746A (en) * | 1970-04-29 | 1974-05-22 | Newlove B | Fibreglass moulding process |
| GB1319477A (en) * | 1970-09-04 | 1973-06-06 | Formica Int | Process for the production of fibre-reinforced thermoset resinarticl |
| US4091061A (en) * | 1974-07-05 | 1978-05-23 | Engins Matra | Method for the production of mouldings containing reinforcing fibre type filler |
| US4075266A (en) * | 1976-11-01 | 1978-02-21 | Friedrich Theysohn | Method for coating foil material |
| US4834933A (en) * | 1981-07-01 | 1989-05-30 | Union Carbide Corporation | Method of molding fiber reinforced articles |
| JPS5866390A (en) * | 1981-10-15 | 1983-04-20 | 日立化成工業株式会社 | Method of producing printed circuit copper-lined laminated board |
| US4474942A (en) * | 1982-06-28 | 1984-10-02 | Takeda Chemical Industries, Ltd. | Cross-linked polyesteramide from bis(2-oxazoline) |
| JPS6088038A (en) * | 1983-10-21 | 1985-05-17 | Takeda Chem Ind Ltd | Production of thermosetting resin |
| JPS6090219A (en) * | 1983-10-21 | 1985-05-21 | Takeda Chem Ind Ltd | Production of thermosetting resin |
| DE3444921A1 (en) * | 1984-02-24 | 1985-09-05 | VE Wohnungsbaukombinat "Wilhelm Pieck" Karl-Marx-Stadt, DDR 9044 Karl-Marx-Stadt | Textile composite material for reinforcements and process for the production thereof |
| JPS60252758A (en) * | 1984-05-26 | 1985-12-13 | 三井木材工業株式会社 | Molding of fibrous yarn molding mat |
| DE3434522A1 (en) * | 1984-09-20 | 1986-03-27 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING MOLDED PARTS FROM FIBER REINFORCED RESIN RESIN |
| DE3582571D1 (en) * | 1984-12-07 | 1991-05-23 | Sumitomo Chemical Co | METHOD AND DEVICE FOR PRODUCING A LAYERED BODY. |
| JPS62117730A (en) * | 1985-11-19 | 1987-05-29 | Puramatsuku Kk | Finish processing of edge of integrally molded part of cloth and resin |
-
1987
- 1987-12-17 DE DE8787118766T patent/DE3780928T2/en not_active Expired - Fee Related
- 1987-12-17 EP EP87118766A patent/EP0272635B1/en not_active Expired - Lifetime
- 1987-12-18 CA CA000554779A patent/CA1289318C/en not_active Expired - Lifetime
- 1987-12-19 KR KR1019870014618A patent/KR950012870B1/en not_active IP Right Cessation
-
1989
- 1989-04-24 US US07/342,598 patent/US4986948A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| KR880007214A (en) | 1988-08-26 |
| EP0272635A2 (en) | 1988-06-29 |
| DE3780928T2 (en) | 1992-12-24 |
| KR950012870B1 (en) | 1995-10-23 |
| EP0272635B1 (en) | 1992-08-05 |
| EP0272635A3 (en) | 1989-03-08 |
| US4986948A (en) | 1991-01-22 |
| DE3780928D1 (en) | 1992-09-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |