JP3755257B2 - Method for manufacturing recycled sheet from carpet waste - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for recycling carpet waste.
[0002]
[Prior art]
In recent years, there has been an increasing demand for recycling carpet waste, especially carpets for automotive applications. This type of carpet is a tufted carpet in which pile yarn is tufted on a base fabric or a needle punched carpet in which short fibers are hardened with needles. Is.
The carpet waste material is generated as a trimming loss after the outer periphery of the product is cut into a required shape in the production process, and the carpet laid when the automobile or the like is discarded may be collected separately. The composition of the waste material is mainly composed of thermoplastic resin such as nylon, polyester, polypropylene as carpet pile yarn, polyethylene as backing, ethylene vinyl acetate, and the like.
[0003]
There are two conventional ways to recycle this type of carpet waste. One is an example in which carpet waste is crushed as finely as possible (preferably pulverized into a powder form) and used as a filler or an extender while maintaining a solid form. For example, Japanese Patent Application No. 57-116935 relates to a vehicle carpet using recycled carpet trimming waste and a method for manufacturing the same, and includes a layer made of recycled carpet trimming waste and a layer made of virgin resin material. Constructed for carpet backing. This is simple recycling in terms of process, but the waste material is pulverized, so it is difficult to produce a new member by secondary processing, and there is no use other than fillers and fillers, making it suitable for recycling applications. There was a quantitative limit.
[0004]
The second conventional aspect of recycling carpet waste is an example of heating and melting carpet waste mainly composed of thermoplastic resin, homogenizing (mixing a compatibilizer), and repelletizing. there were. For example, Japanese Patent Application No. 3-208894 pulverizes a waste material of a nylon pile carpet and melt kneads it with a maleic anhydride-modified polyolefin and a peroxide compound. According to this kind of recycling, it is possible to secondary process the obtained recycled pellets and recycled sheets, and there are various and large volume recycling applications.
[0005]
When the carpet waste material is heated and melted for recycling, there are the following problems.
(1) Many carpets of this type are backed by a backing, but a chlorine-based flame retardant is often mixed in the backing material. This is to meet safety standards for preventing combustion of automobiles and buildings. When waste material containing a chlorine-based resin is heated, decomposition occurs at a relatively low temperature (about 150 ° C.), and there is a risk of generating harmful chlorine gas. Therefore, conventionally, it has been necessary to separate and exclude carpet waste materials that may contain chlorine-based flame retardants prior to this type of recycling.
(2) Carpet waste collected from scrapped vehicles, etc. contains foreign matters such as fine sand (although these are non-melted and incompatible with carpet waste), they are completely removed for recycling. It is impossible. Re-pelletizing (melting treatment) waste material with a lot of foreign matters not only affects the quality but also causes a failure of the processing machine. In addition, this type of incompatible and non-melting contaminants include cotton fibers in felts that are stuck to carpets, and even thermoplastic resins have an extremely high melting point with other resins. If different materials are included, the temperature at which one is melted reaches the decomposition temperature of the other resin, so that some cannot be melted and remain.
(3) The amount of energy required for recycling waste materials tends to be large, increasing the cost of recycling.
[0006]
[Problems to be solved by the invention]
The present invention has been considered in view of the above problems, and is a method for producing a recycled sheet by recycling a carpet waste material containing a readily decomposable flame retardant such as a vinyl chloride resin. Provided is a manufacturing method capable of sheeting even when foreign matter is included.
[0007]
[Means for Solving the Problems]
The means of the present invention for solving the problem is that at least the following in manufacturing a recycled sheet from carpet waste material: (a) 5-50% by weight of a pulverized waste product of carpet, 0-80% by weight of filler, and a temperature of 110 A binder resin containing 15 to 50% by weight of an amorphous polyolefin resin having a fluidity at 1 to 10 min at a melt flow rate value (2.16 kgf) at this temperature of 110 ° C. to 140 ° C. at a temperature of 110 ° C. A step of kneading so that the pile yarn component of the carpet waste material remains unmelted at ˜140 ° C., and (b) the obtained kneaded material is put into an extruder and extruded into a sheet form from a T die. a step, by a method for producing a recycled sheet from carpet waste, characterized by comprising with each step process of rolling the sheet extruded (c) According to the present invention, since the temperature reached by the carpet waste is 140 ° C. or less, even if the waste contains a readily decomposable flame retardant such as chlorine, it may be decomposed and vaporized at this temperature. There is no. When the temperature of carpet waste reaches 110 ° C, the plasticity of the blended binder resin increases and the entire waste becomes easy to flow, so it is possible to knead while leaving the incompatible and non-molten components in the waste. And enables sheeting by a sheet extruder. In order to increase the plasticity at such a low temperature, it is necessary that the binder resin has a high fluidity at a low temperature. In the present invention, this is achieved by blending an amorphous polyolefin resin having a low crystallinity. Yes. The temperature of the carpet waste can be raised naturally by pressurization, and almost no heat supply from the outside is required. Therefore, it is excellent in energy efficiency, and the cost of recycling can be reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
Suitable for (carpet waste) invention is formed by applying a backing of thermoplastic in tufted carpet or needle punch carpet comprising a thermoplastic resin as a main component. It is also possible to use a material containing a filler in the lining, or a non-separable laminate of non-thermoplastic cotton felt through the lining. The method of the present invention is particularly suitable for the case where the lining thermoplastic resin contains a chlorinated flame retardant, a vinyl chloride resin and a copolymer thereof, or the case where the carpet contains vinyl chloride fibers. As a specific example, a nylon tuft carpet for automobiles (when the base fabric is polyester and the backing is massback, the waste material composition is nylon resin 40 to 50% by weight, polyester 10 to 15% by weight, ethylene vinyl acetate resin 10-30% by weight, calcium carbonate 10-40% by weight), polypropylene needle punch carpet (in the case of backing polyethylene resin and SBR-based latex, the waste material composition is 20-50% by weight polypropylene resin, 20-50% by weight polyethylene resin) SBR resin 5 to 20% by weight, vinyl chloride resin 5 to 20% by weight).
[0009]
(Filler) A filler having high specific gravity is suitable for use. Specifically, organic and inorganic particles having a molecular composition such as CaCO ₃ and BaSO ₄ , talc, automobile bumper waste, metal powder, and the like are possible.
(Binder resin) A non-crystalline polyolefin resin having sufficient fluidity at a temperature of 110 to 140 ° C. (preferably at this temperature at a melt flow rate of 1 g / 10 min or more and a load of 2.14 kgf) is blended. Is suitable. Particularly preferred is an amorphous polyolefin resin manufactured by Ube Lexen Corporation, trade name APAO. Since this resin has high fluidity and adhesiveness at low temperatures and has flexible properties even at room temperature, it can take in a large amount of (non-melted and incompatible) fillers and still maintain high fluidity.
[0010]
(Combination)
5 to 50% by weight of the carpet waste material, 0 to 80% by weight of the filler, and 15 to 50% by weight of the binder resin are suitable.
These figures are obtained empirically, and the blending depends on the conditions of the carpet waste material, but the blending ratio of the carpet waste material and the filler is high and the blending ratio is too low. The fluidity of the resin is low, making it unsuitable for extrusion processing, or causing problems such as the resulting sheet being easily broken.
The higher the ratio of the binder resin, the more expensive the recycled sheet obtained and the lower the value of recycling.
[0011]
(Kneading machine)
The waste material is preferably kneaded by a kneader, and a screw kneader or the like can also be used. In particular, in the case of the present invention, since the ultimate temperature of the waste material is 140 ° C. or less, the waste material self-heats by stirring while applying a shearing force to the waste material with a blade by a pressure kneader, and the target temperature can be obtained without heating. Can be reached. When there is a possibility that the temperature of the waste material exceeds 140 ° C., it is cooled by installing a water jacket or the like, and the waste material temperature is controlled to 110 to 140 ° C. At this temperature, except for the low melting point portion of the carpet waste, components such as pile yarn having a high melting point remain unmelted.
(Extruder)
The kneaded material kneaded with a kneader or the like is extruded by an extruder. A screw extruder, particularly a biaxial taper type, is suitable. Extrusion speed 0.5-5 m / min, T die lip interval 1.0-10 mm.
(rolling)
Rolling is a rolling roll (mirror roll type, internal water cooling), and is cooled by rolling to a sheet of 0.5 to 5 mm. (Compression rate 20-80%)
(Evaluation of the obtained sheet)
The sheet obtained by the present invention had the following characteristics.
The thickness is 0.5 to 5 mm, the density is 1.0 to 3.0 g / cm ³ , the touch is flexible, and there is some plasticity at room temperature. Although the appearance is a uniform sheet, the carpet waste fibers remain inside, so it is tough and sticky and hard to break.
When the sound insulation was measured, the performance was comparable to a vinyl chloride resin sheet having the same basis weight.
[0012]
【The invention's effect】
According to the present invention, it is possible to recycle and seat carpet waste while leaving a vinyl chloride resin-based flame retardant, which has been difficult to recycle, to remain incompatible and non-melted.
The obtained recycled sheet is excellent in flexibility and toughness and can be secondary processed. Moreover, it exhibits excellent performance as a sound insulation sheet, and can replace a conventional vinyl chloride resin sound insulation sheet.

Claims (1)

Of at least the following from carpet waste to produce a recycled sheet,
(A) 5 g to 50 wt% of the waste carpet pulverized product, 0 to 80 wt% of the filler , and 1 g of fluidity at a temperature of 110 ° C. to 140 ° C. at a melt flow rate value (2.16 kgf) at this temperature / 10min or more of binder resin containing amorphous polyolefin resin containing 15 to 50% by weight so that the pile yarn component of the carpet waste material remains unmelted at a temperature of 110 ° C to 140 ° C in a kneader. A kneading step;
(B) a step of putting the obtained kneaded material into an extruder and extruding it from a T-die into a sheet;
(C) rolling the extruded sheet ;
A method for producing a recycled sheet from waste carpet material, comprising the steps of: