WO2011140628A1

WO2011140628A1 - Process for producing recycled paper

Info

Publication number: WO2011140628A1
Application number: PCT/CA2011/000503
Authority: WO
Inventors: Rajan Ahluwalia
Original assignee: Rajan Ahluwalia
Priority date: 2010-05-12
Filing date: 2011-04-29
Publication date: 2011-11-17
Also published as: CA2797038A1; CA2703595A1

Abstract

A method for producing recycled paper is provided. Paper pulp and cotton pulp are provided. The cotton pulp is added to the paper pulp to produce a pulp mixture. The pulp mixture is deposited onto a wire mesh for forming a paper web such that a flow rate of the pulp mixture and a speed of a relative movement between a pulp mixture depositing device and the wire mesh is reduced compared to the flow rate and the speed of the relative movement used for depositing only the paper pulp.

Description

PROCESS FOR PRODUCING RECYCLED PAPER

FIELD OF THE INVENTION

The present invention relates to the field of paper production, and more particularly to a process for producing recycled paper using waste paper and waste cotton material.

BACKGROUND OF THE INVENTION

Modern technology in present day paper mills and highly mechanised technologies for harvesting wood made paper a relatively cheap commodity resulting in a high level of consumption and waste. Worldwide consumption of paper has risen by 400% in the past 40 years with 35% of harvested trees being used for paper manufacture raising substantial environmental issues. Due to the rise of environmental awareness in the general public and government regulations there is now a trend towards sustainability in the pulp and paper industry.

The rise of environmental awareness is reflected in the increasing implementation of recycling of waste materials such as waste paper and waste clothing. An increasing amount of waste paper such as, for example, office paper and newspaper is collected and used in the manufacture of new paper.

Unfortunately, with reuse the length of the paper fibres decreases resulting in a substantially reduced strength of the final paper product. Typically, a small amount of paper pulp made from waste paper is mixed with a large amount of wood pulp made from harvested trees in the manufacture of higher quality paper.

Another method of making paper is the use of cotton fibres producing high quality cotton paper of exceptional strength which is generally used for making bank notes.

Attempts to use cotton fibres for strengthening paper made from recycled waste paper have failed due to problems in mixing and adhering of the waste paper and cotton fibres. It is desirable to provide a process capable of mixing and adhering waste paper and cotton fibres for producing paper.

It is also desirable to provide a process for paper manufacturing using only waste paper and waste cotton material.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide a process capable of mixing and adhering waste paper and cotton fibres for producing paper.

Another object of the present invention is to provide a process for paper manufacturing using only waste paper and waste cotton material.

According to one aspect of the present invention, there is provided a method for producing recycled paper. Paper pulp and cotton pulp are provided. The cotton pulp is added to the paper pulp to produce a pulp mixture. The pulp mixture is deposited onto a wire mesh for forming a paper web such that a flow rate of the pulp mixture and a speed of a relative movement between a pulp mixture depositing device and the wire mesh is reduced compared to the flow rate and the speed of the relative movement used for depositing only the paper pulp.

According to another aspect of the present invention, there is further provided a method for producing recycled paper. Paper pulp and cotton pulp are produced from waste paper and waste cotton material, respectively. The cotton pulp is added to the paper pulp to produce a pulp mixture. The pulp mixture is deposited onto a wire mesh for forming a paper web such that a flow rate of the pulp mixture and a speed of a relative movement between a pulp mixture depositing device and the wire mesh is reduced compared to the flow rate and the speed of the relative movement used for depositing only the paper pulp. Furthermore, the wire mesh has a reduced mesh size compared to the mesh size used for depositing only the paper pulp. The advantage of the present invention is that it provides a process capable of mixing and adhering waste paper and cotton fibres for producing paper.

A further advantage of the present invention is that it provides a process for paper manufacturing using only waste paper and waste cotton material.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is described below with reference to the accompanying drawings, in which:

Figures la to Id are simplified flow diagrams illustrating a process for producing recycled paper according to a preferred embodiment of the invention; and,

Figures 2a to 2c are simplified block diagrams illustrating a preferred implementation of the process for producing recycled paper illustrated in Figures la to Id.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.

Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described.

While embodiments of the invention will be described for implementation using a Fourdrinier type paper making machine, use of waste paper for producing paper pulp, and use of waste cotton material for producing cotton pulp for the sake of simplicity, it will become evident to those skilled in the art that the embodiments of the invention are not limited thereto, but are also applicable using different paper making machines, paper pulp made using wood, cotton pulp made using new cotton fibers as well as combinations with waste paper and waste cotton material.

Referring to Figures la to Id, a process for producing recycled paper according to a preferred embodiment of the invention is provided. A preferred implementation 100 of the process for producing recycled paper is illustrated in Figures 2a to 2c. At 10A and 10B, paper pulp and cotton pulp is provided, respectively. Preferred embodiments for providing the paper pulp and the cotton pulp are illustrated in Figures lb and lc, respectively. Preferably, waste office paper collected from various offices or elsewhere is fed into a pulper. The pulper is mixer and grinder, where a predetermined amount of the waste paper is mixed with a predetermined amount of water and ground at high speed - 10A.1. At 10A.2, preferably four percent aluminum sulphate and four percent rosin are added to the paper pulp. Aluminum sulphate is added for sizing the stock and for making the paper blot free. Rosin is added for binding the fibers together. As is evident to those skilled in the art, other materials and amounts are applicable depending, for example, on the type of material used for producing the paper pulp and the type of recycled paper to be produced. At 10A.3, ferrous materials such as, for example, pins, staples, and clips are removed from the paper pulp. The removal of the ferrous materials is performed, for example, by lowering magnets into the paper pulp during the mixing and grinding process. After termination of the pulping the paper pulp is processed - 10A.4 - to remove unwanted non-ferrous material such as, for example, pieces of plastic material. For example, the paper pulp is passed through a screen having a predetermined mesh size large enough for enabling transmission of the paper pulp fibers and small enough to prevent transmission of substantially all unwanted materials. The screened paper pulp is then transferred into an agitator 102 for agitating the paper pulp - 10A.5. A typical agitator 102 is a round well with a motor driven shaft having two or more blades 104 mounted thereto. A slow movement of the blades 104 ensures provision of a consistent paper pulp 106.

Using only waste paper for producing the paper pulp does not provide recycled paper having sufficient strength for most types of paper. To increase the strength of the recycled paper, cotton fibers are added. Preferably, waste cotton materials such as, for example, waste cotton clothes or cuttings and trimmings from garment factories are used for providing the cotton fibers. At 10B.1, the waste cotton materials are sorted, for example, to sort colored cotton materials, and extra fittings such as, for example, buttons and zippers are removed. For example, only cotton materials of a specific color are used for a specific recycled paper product to be produced there from. Mixed color stock is used for producing low grade packaging materials. The cotton material is then cut to a substantially uniform size - 1 OB.2. A predetermined amount of the cut cotton material is then fed into a beater 108 together with a predetermined amount of water and beaten - 10B.3 - for approximately 5 hours using beating element 110 for producing cotton pulp 112.

After approximately three hours of beating, preferably four percent rosin is added to the cotton pulp - 10B.4 - and after four hours of beating aluminum sulphate is added to the cotton pulp - 10B.5. Aluminum sulphate is added for sizing the stock and for making the recycled paper blot free. Rosin is added for binding the fibers together. As is evident to those skilled in the art, other materials and amounts are applicable depending, for example, on the type of cotton material used for producing the cotton pulp and the type of recycled paper to be produced. The cotton pulp is then washed - 10B.6 - to remove unwanted materials.

The cotton pulp 1 12 is then added to the paper pulp 106 to produce a pulp mixture - 20. For example, the cotton pulp is slowly added to the paper pulp while the same is agitated in the agitator 102. The pulp mixture is agitated - 30 - to ensure provision of a consistent pulp mixture. Depending on the required strength of the recycled paper product a predetermined amount of cotton pulp is added to the paper pulp. For example, for producing recycled paper products for office stationary, filters, and insulation the amount of cotton pulp added is approximately in the range between 15% and 25% of the paper pulp. Mixing and adhering of the paper pulp fibers and the cotton pulp fibers is substantially improved by adding the cotton pulp to the paper pulp.

Once the pulp mixture is consistent it is provided - 40 - to a headbox 1 18 of a paper making machine such as, for example, a Fourdrinier type paper making machine. For example, the pulp mixture is pumped to the headbox 1 18 using a conventional pulp pump. Depending on the thickness of the recycled paper to be manufactured the pulp mixture is diluted with water 114. The diluted pulp mixture 1 16 is then deposited - 50 - onto a conveying wire mesh 124 forming a paper web of the paper making machine. For example, the diluted pulp mixture 1 16 flows under gravity through nozzle 120 of the headbox 1 18 as indicated by arrow 122 and onto the wire mesh 124 forming pulp layer 126. The pulp layer 126 is then conveyed via the conveying wire mesh - as indicated by the arrow - from the headbox 1 18 to further processing stations of the paper making machine for producing - 60 - paper therefrom, as will be described herein below. To ensure adherence of the paper pulp fibers and the cotton pulp fibers the diluted pulp mixture 116 is deposited onto the wire mesh 124 such that a flow rate of the pulp mixture and a speed of a relative movement between the nozzle 120 the wire mesh 124 is reduced compared to the flow rate and the speed of the relative movement used for depositing only the paper pulp. Preferably, the flow rate as well as the speed of the relative movement is reduced by approximately 25% to 45%. Furthermore, the mesh size the conveying wire mesh 124 is reduced, as illustrated in Figures 2b and 2c. Preferably, the mesh size is reduced by approximately 20% to 35%. As is evident, the process for producing recycled paper is also implementable with types of paper making machines including paper making machines having a stationary wire mesh and movable headbox.

The pulp layer 126 - or paper sheet - is then processed to remove a first portion of the water - 60.1 - followed by passing it through a plurality of rollers for further drying and calendaring - 60.2. In the calendaring process the paper is passed between two rollers pressing the paper. The calendaring process further dries the paper and gives it a glazing effect. After calendaring the paper is, for example, rolled onto a roller - 60.3 - forming a paper roll for further processing such as printing or, alternatively, cut into sheets and packed in a packet or reem.

The process for producing recycled paper according to embodiments of the invention enables production of recycled paper in small quantities for recycling waste paper and waste cotton clothing in smaller communities. Furthermore, the process for producing recycled paper is easily implementable by modifying existing paper making machines to reduce the relative speed between the headbox and the wire mesh and reducing the mesh size.

The present invention has been described herein with regard to preferred embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method comprising:

providing paper pulp;

providing cotton pulp;

adding the cotton pulp to the paper pulp to produce a pulp mixture;

providing a wire mesh for forming a paper web; and,

depositing the pulp mixture onto the wire mesh such that a flow rate of the pulp mixture and a speed of a relative movement between a pulp mixture depositing device and the wire mesh is reduced compared to the flow rate and the speed of the relative movement used for depositing only the paper pulp.

2. A method as defined in claim 1 wherein a wire mesh is provided having a reduced mesh size compared to the mesh size used for depositing only the paper pulp.

3. A method as defined in claim 2 comprising producing the paper pulp from waste paper.

4. A method as defined in claim 3 comprising producing the cotton pulp from waste cotton material.

5. A method as defined in claim 1 wherein the cotton pulp is added while agitating the paper pulp.

6. A method as defined in claim 4 comprising adding rosin and aluminum sulphate to the cotton pulp.

7. A method as defined in claim 4 wherein the pulp mixture is deposited from a stationary headbox onto a moving wire mesh conveyor.

8. A method as defined in claim 1 wherein the pulp mixture is deposited such that the flow rate and the speed are reduced by 25% to 45%.

9. A method as defined in claim 8 wherein a wire mesh is provided having a mesh size that is reduced by 20% to 35% compared to the mesh size used for depositing only the paper pulp.