GB1574006A

GB1574006A - Articles comprising intermingled paper strips

Info

Publication number: GB1574006A
Application number: GB5117375A
Authority: GB
Original assignee: Dunlop Ltd
Current assignee: Dunlop Ltd
Priority date: 1977-03-14
Filing date: 1977-03-14
Publication date: 1980-09-03

Description

(54) ARTICLES COMPRISING INTERMINGLED PAPER STRIPS (71) We, DUNLOP LIMITED, a British Company of Dunlop House, Ryder Street, St.

James's, London S.W.1., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to articles comprising intermingled paper strips.

According to the present invention there is provided an article comprising an assembly of at least one paper strip randomly and coherently intermingled in three dimensions.

Although a single strip may be employed it is preferred to employ a multitude of strips. The word 'strip' is used in its ordinary sense to mean a thin sheet which is long in one direction compared to the perpendicular direction in the sheet plane. When more than one strip is employed the maximum strip length:width ratio may be as low as 3:1 but generally greater ratios are desirable to give satisfactory intermingling. Preferably the strips should have a length: width ratio of at least 10:1, more preferably in the range 16:1 to 24:1, especially when they are intermingled by hand. Very long strips are generally not preferred because of the difficulty of achieving uniform distribution in the product and the difficulty of achieving uniform mixing with any other ingredients. A mixture of strips of various sizes may be employed. Suitable strips may be made by shredding paper sheets in a conventional document-shredding machine. Preferably the length of at least some of the strips is at least equal to the thickness of the strip assembly.

The invention is suitable for utilising scrap paper, e.g. old newspapers, magazines, telephone directories, reports, letters, cardboard and kitchen towels.

Although a coherent product can be obtained by intermingling a strip or strips in the absence of other ingredients, it is preferred to employ a binder to improve the cohesion and, if desired, to provide a stronger and/or harder product. A suitable binder may be a resinous or polymeric binder which may be thermoplastic or thermoset in the final article. Examples of suitable polymers and resins are phenolic resins, poly(vinyl chloride), vinyl chloride/vinyl acetate copolymers, wood resins (e.g. wood rosin), urea/formaldehyde resin, polyurethane, bitumen, polystyrene and polyethylene. The ratio of paper to binder and the other conditions of production of the article will determine the properties such as porosity, strength and hardness of the article. For a microporous article such as could be employed for sound- and heat-insulation a binder in an amount of about 5 to 6 parts by weight per 100 parts by weight of paper is suitable. For denser stronger articles such as structural board a preferred amount of binder may be at least 10 parts by weight per 100 parts by weight of paper. These figures are based on the use of strips of newspaper. Obviously the suitable amounts may differ for kinds of paper having different properties such as stiffness and absorbency. It is found that a strong product can be obtained using a relatively small proportion of binder when the paper is in strip form rather than in other forms.

Other ingredients may be in admixture with the strip or strips with or without binder. For instance, paper in non-strip form, colouring agents and flame-retardants (e.g. alumina hydrate or inorganic fillers such as whiting) may be present.

The intermingling of the strip or strips and/or the admixture of binder and/ or one or more other ingredients may be achieved manually or mechanically. Suitable strip intermingling for many purposes may be achieved merely by allowing the strip or strips to fall in random fashion onto a press or mould surface. The binder may be incorporated in the form of a liquid or a solid. When in liquid form it may be applied to the strip(s) by, for example, spraying or dipping. However, a preferred form of the binder for mixing with the strip(s) is a solid particulate form. Alternatively the binder may be applied to the strip(s) by electrostatic coating. This latter method has the advantage that it is largely independent of the absorbency of the paper. Where a solid binder is admixed with the strip(s) it should be subsequently melted, suitably during a compression or moulding step.

It is found that the method employing a particulate binder offers advantages over the use of a liquid binder. For instance, it is found that in order to obtain an article having a certain strength and hardness, a significantly small proportion of solid particulate binder is required in comparison with the proportion of liquid binder required to achieve the same strength and hardness. Also the method employing solid binder particles enables the production of a strong article having minute voids which make it suitable as an insulation material whereas in order to obtain the same strength using a liquid binder the necessary larger proportion of binder would result in a product having no or significantly fewer voids and consequently poorer insulation character. Furthermore, the method employing solid binder particles obviates a drying step.

The article is preferably made by moulding or compressing an assembly of intermingled strip(s) and/or other ingredients. The degree, temperature and time of compression will obviously depend on the materials employed and the product desired. For hard wood-like products a suitable pressure has been found to be in the range 150 to 200 lb/in2. The strip assembly may be moulded around a former to produce a hollow article.

The article may comprise a laminate of the intermingled strip(s) with one or more sheet materials acting as, for example, strengthening and/or protective and/or decorative layers.

Examples of sheet materials which may be employed are wood, plastics and paper. The sheets may be bonded to the strip assembly during or after compression or moulding of the assembly. A resin-soaked paper sheet may be suitably assembled with the strip assembly prior to or during moulding, whereas it is found that a poly(vinyl chloride) sheet is preferably bonded to the strip assembly after moulding.

By selection of materials and conditions the articles of this invention may be weakly cohesive or hard and strongly cohesive. It is possible to make wood-like articles by compressing assemblies of strips and binder. Such articles are capable of receiving nails and screws and can be sawn, sanded, filed and chiselled similarly to wooden articles. It is found that the edges of a wood-like sheet made in accordance with the invention may have a 'wood-grain' appearance when sanded and varnished.

Examples of articles in accordance with the present invention are sheet materials useful as wall coverings, building partitions and other structural boards, sound and heat insulation materials and packaging material, and mouldings for example doors having integral panels and frame.

The invention is illustrated in the following Examples.

EXAMPLE I The following ingredients were mixed together by shaking manually in a transparent polythene bag until a uniform mixture was apparent to the eye: 765 g of Cellobond J1013H resin ("Cellobond" is a registered Trade Mark) being a phenolic resin containing 10% (of total weight) hexamethylene tetramine, in the form of particles of which 0.1 % was retained on a British Standard 60 mesh sieve, 1 was retained on a B.S. 120 mesh sieve, 5%was retained on a B.S. 200 mesh sieve, and the remainder passed through the B.S. 200 mesh sieve.

1530 g hydrated alumina powder available under the trade name Baco FRF. 40 (ex. British Aluminium Chemicals Ltd.) ("Baco" is a registered Trade Mark), having a mean particle size of about 1 x 10- m as measured by Andreasen sedimentation and such that all of the particles passed through a British Standard 200 mesh (i.e. 75 x 10-6m) sieve, 0.1%was retained on a B.S. 300 mesh (53 x 10-6m) sieve and 0.3was C?o was retained on a B.S. 350 mesh (45 x 10~6m) sieve.

3900 g paper strips obtained by shredding a mixture of scrap paper such as newspaper, telephone directories, office reports, accounts and cardboard, in a conventional document shredder to give strips having a width of about 41 inch (6.4 mm) and a length depending on the raw material.

The mixture was spread out over an area of 16 ft2 (14864 cm2) in a steam-heated hydraulic press and compressed to a thickness of 1 cm at 1500C. for 20 minutes to cure the resin.

The product was very compacted. It was about as strong as conventional chipboard and was suitable for indoor construction purposes. The paper strips could not be separated by hand.

Division into smaller pieces required sawing.

EXAMPLE II The procedure of Example I was repeated except that the thickness to which the mixture was compressed was 2 cm.

The product contained voids and was suitable for insulation purposes. It may be a suitable substitute for plasterboard.

When a Bunsen flame was played onto a face of the sheet for 2 minutes no burning occurred outside the contacted area.

EXAMPLE III The procedure of Example I was repeated with the following modification. The sheet material was compressed at room temperature for 30 seconds in the press to a thickness in the press of 1 cm. The press was then opened and a sheet of Vynolay (a pvc floor-covering material) having a thickness of about 1.5 mm was placed on the top surface of the sheet material. The assembly was then compressed at 1 800C. for 20 minutes to a thickness of about 11.5 mm. The steam was then switched off and cooling water was admitted before the press was opened and the laminated material removed. (If the press is not cooled before the assembly is removed the pvc has a tendency to blister).

The product was suitable for outside construction purposes.

EXAMPLE IV 500 g of -41-inch wide newspaper pieces having one of the lengths given in the following tables were placed together with 50 g, 75 g or 100 g of "Cellobond" J1013H resin particles defined in Example I in a one-gallon cylindrical container and were tumble-mixed until the maximum degree of mixing was achieved, namely after about 35-40 minutes. The mixture was then emptied out onto one of a pair of 18 in2 press platens and spread into a layer of approximate dimensions 15 x 9 x 5 inches. The layer was then pressed between the platens at 180 Ib/in2 and 1300C. for 15 minutes to result in a coherent sheet of thickness 0.275 inch.

6 x 2 inch specimens were cut from the sheet and subjected to a bend strength test by bending each specimen to breaking point over a inch diameter mandrel, the distance between the gripping points being 3 inches. The results are given below, each figure representing the mean of four tests.

Paper Length Bend StrS blgth (lob) for Resin (inches) Amounts (gJ of- 10 15 20 4 91 110 137 1 134 183 218 2 166 185 184 i-inch wide specimens were cut from the sheet made using 10 g resin and were tested for tensile strength by pulling along the length of the specimen between gripping jaws. The results are given below: Paper Length Tensile Strength (inches) (lb/ 21 in) 4 127 1 264 2 272 4 301 These results show a significant difference between the strength of the specimens made from non-strip paper ( 4 x 41 inch) and the strength of the specimens made from paper strips, and show that tensile strength increases with increasing specimen strip length. This is a consequence of the increased intermingling with increasing strip length.

EXAMPLE V This Example illustrates the preparation of an article in the absence of a binder.

4 x -41-inch newspaper strips were emitted from a paper shredder directly onto one of a pair of 18 in2 press platens and were spread to a thickness of about 5 inches over an area of about 15 x 9 inches. The collection of strips was pressed between the platens at 180 lb/in2 and 130"C. for 15 minutes. The product was found to have a thickness of about 4 inch and to be handleably united as a result of intermingling of the strips. It was suitable as an interlayer in sound-insulation board.

This procedure was repeated with the same weight of newspaper in 4 x 4 inch pieces. There was no intermingling of these pieces or unity of the product.

WHAT WE CLAIM IS: 1. An article comprising an assembly of at least one paper strip randomly and coherently intermingled in three dimensions.

2. An article according to claim 1 comPrising a multitude of strips.

3. An article according to claim 1 or 2 which comprises at least one strip of scrap paper.

4. An article according to any of the preceding claims comprising at least one paper strip produced by shredding in a document-shredding machine.

5. An-article according to any of the preceding claims in which the assembly is moulded or compressed.

6. An article according to any of the preceding claims in which the assembly is laminated with one or more sheet materials.

7. An article according to any of the preceding claims in which the assembly includes a binder.

8. An article according to claim 7 in which the binder is a resinous or polymeric binder.

9. An article according to claim 8 in which the polymer or resin of the binder is selected from phenolic resin, poly (vinyl chloride), vinyl chloride/vinyl acetate copolymers, wood resins, urea/formaldehyde resin, polyurethane, bitumen, polystyrene and polyethylene.

10. An article according to any of claims 7-9 in which in the manufacture of the article a binder in solid particulate form is mixed with the strip or strips.

11. An article according to any of claims 7-9 in which in the manufacture of the article a binder is applied to the strip or strips by electrostatic coating.

12. An article according to any of claims 7-11 in which the amount of binder is 5 to 6 parts by weight per 100 parts by weight of paper.

13. An article according to any of claims 7-11 in which the amount of binder is at least 10 parts by weight per 100 parts by weight of paper.

14. An article according to any of the preceding claims comprising a multitude of strips having a minimum strip length:width ratio of at least 3:1.

1 5. An article according to any of the preceding claims comprising a strip or strips having a length:width ratio of at least 10:1.

16. An article according to any of the preceding claims comprising a strip or strips having a length:width ratio in the range 16:1 to 24:1.

17. An article according to any of the preceding claims comprising a mixture of strips of various sizes.

18. An article according to any of the preceding claims comprising a strip or strips having a length which is at least equal to the thickness of the assembly.

19. An article according to any of the preceding claims in which in the manufacture of the article the assembly has been compressed in the range 150 to 200 Ib/in2.

20. An article according to any of the preceding claims in which the assembly is laminated with at least one plastics sheet.

21. An article according to any of the preceding claims in which the assembly is laminated with at least one resin-soaked paper sheet.

22. An article according to claim 1 and substantially as described in any of Examples I to III.

23. An article according to claim 1 and substantially as described in Example IV or V.

24. The use of an article according to claim 1 as a wall covering, building partition or other structural board, sound or heat insulation material or packaging material.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. sound-insulation board. This procedure was repeated with the same weight of newspaper in 4 x 4 inch pieces. There was no intermingling of these pieces or unity of the product. WHAT WE CLAIM IS:

1. An article comprising an assembly of at least one paper strip randomly and coherently intermingled in three dimensions.

2. An article according to claim 1 comPrising a multitude of strips.