JPH0726075B2 - Adhesive composition for carpet backing - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive composition for lining a carpet used as an interior material for automobiles.

[Conventional technology]

Needle punched carpets and tufted carpets for automobile interiors are obtained by applying or impregnating an adhesive composition containing styrene-butadiene copolymer latex or ethylene-vinyl acetate resin emulsion as a main component to the back surface of the carpet, It is manufactured by a two-step processing method in which a thermoplastic resin film such as polyethylene is lined by heat fusion in order to impart thermoformability.

These carpets are cut, molded by press molding at the time of heating according to the shape of the floor of the automobile, and then incorporated into the automobile.

On the other hand, unlike the above-mentioned two-step processing method, a so-called one-step processing method is disclosed in Japanese Patent Laid-Open No. 53-52776, in which an aqueous plastic dispersion is applied to the back surface of a carpet to obtain a continuously moldable carpet. ing.

[Problems to be solved by the invention]

In the conventional two-step processing method, the non-woven fiber or pile system is fixed by coating or impregnating an adhesive consisting of an aqueous emulsion of styrene-butadiene copolymer latex or resin, and further, a film of thermoplastic resin is lined. This gives the carpet thermoformability, but such a two-step processing method complicates the carpet manufacturing process, and therefore improvement thereof has been desired.

On the other hand, in the one-step processing method for imparting thermoformability to the adhesive without backing the thermoplastic resin film, the thermoformability and the ability to maintain its shape (called shape retention) ) Is not sufficient, and there is a problem that if the thermoformability and the shape-retaining property are to be improved, the fixing force of the fiber is lowered.

Therefore, it has been desired to develop a backing adhesive composition that can be processed in one step and is excellent in all aspects of thermoformability, shape retention, and fiber adhesion.

[Means for solving problems]

In order to solve such a problem, the inventors of the present invention have conducted earnest research on a one-step processable adhesive composition for carpet backing, and as a result, have been proposed in Japanese Patent Laid-Open No. 53-52776. Rather than using known aqueous plastic dispersions and mixtures of such dispersions as backing adhesives,
A mixture obtained by mixing a copolymer latex (A) having a specific glass transition point and a specific particle size and a copolymer latex (B) having a specific particle size in a specific ratio. The present invention has been completed by finding the fact that by using as a backing adhesive, excellent effects are exhibited in all aspects of thermoformability, shape retention and fiber fixing strength.

Structure of the Invention [Structure of the Invention] That is, the present invention is composed of 50-90 wt% α-methylstyrene, 10-50 wt% acrylonitrile and 0-40 wt% other copolymerizable monomers, 110 ℃ ~ 160
Copolymer latex (A) having a glass transition point of 50 ° C. and a particle diameter of 50 to 300 nm, 30 to 70 parts by weight (solid value), butadiene 10 to 90% by weight, styrene 10 to 90% by weight
And another copolymerizable monomer of 0 to 80% by weight, and a particle size of 50 to 300 nm of a copolymer latex (B) of 70 to 30 parts by weight (solid content conversion value). An adhesive composition for carpet backing is provided.

By coating or impregnating the adhesive composition of the present invention on the back surface of a needle punched carpet or a tufted carpet, an automobile carpet having excellent thermoformability and shape-retaining property and excellent fiber adhesion is obtained. Can be easily obtained. Further, unlike the above-described two-step processing method, the present invention does not require the backing of the thermoplastic resin film, so that the carpet manufacturing process can be simplified and the productivity can be improved.

Hereinafter, the present invention will be described in more detail.

Copolymer Latex (A) The copolymer latex (A) used in the present invention is α
-Methylstyrene 50-90% by weight, acrylonitrile 10-
50% by weight and 0 to 40% by weight of other copolymerizable monomer, having a glass transition point of 110 ° C to 160 ° C,
And the particle size is 50 to 300 nm.

When α-methylstyrene is less than 50% by weight, the shape retention is poor,
If it exceeds 90% by weight, the polymerization time becomes long and the productivity becomes poor, which is not preferable. If the amount of acrylonitrile is less than 10% by weight, the polymerization time will be long and the productivity will be poor. If the amount of acrylonitrile is more than 50% by weight, the shape retention will be poor, such being undesirable.

Further, when the glass transition point is 110 ° C. at the end, the shape retention is poor. On the other hand, a large amount of α-methylstyrene is required to obtain a copolymer having a temperature higher than 160 ° C., so that the polymerization time becomes long and the productivity becomes poor, which is not preferable. Particle size less than 50nm and 300n
If it exceeds m, the moldability is deteriorated, which is not preferable. Particle size is 50-1
More preferably 50 nm.

Other copolymerizable monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid and itaconic acid, ethyl methacrylate unsaturated carboxylic acid alkyl esters such as methyl methacrylate and butyl acrylate, and β-hydroxyethyl acrylate, methacrylonitrile, acrylamide and the like can be mentioned. Of these, 0.1-10% by weight of ethylenically unsaturated carboxylic acid
It is preferable to use.

Copolymer Latex (B) The copolymer latex (B) used in the present invention comprises 10 to 90% by weight of butadiene, 10 to 90% by weight of styrene and 0 to 80% by weight of other copolymerizable monomer. It has a particle size of 50 to 300 nm. If the content of butadiene is less than 10% by weight, the fixing strength of the fiber will be poor, and if it exceeds 90% by weight, the moldability will be poor, such being undesirable. If the content of styrene is less than 10% by weight, the moldability will be poor, and if it exceeds 90% by weight, the fixing strength of the fibers will be poor, such being undesirable. Also, if the particle size is less than 50 nm, the shape retention is inferior.
If it exceeds, the fixing strength of the fiber is inferior, which is not preferable. Particle size is
More preferably, it is 50 to 150 nm.

Other copolymerizable monomers include acrylic acid, methacrylic acid, fumaric acid, itaconic acid, methyl methacrylate, butyl acrylate, acrylonitrile, acrylamide, β-hydroxyethyl acrylate, α-methylstyrene and the like.

As a method for adjusting the particle size of the copolymer latex (A) and the copolymer latex (B), a known method can be used. For example, the amount of the emulsifier and the method of adding the monomer are adjusted. Thereby, latexes having different particle diameters can be obtained.

Latex Mixture The latex mixture used in the present invention is copolymer latex (A) 30 to 70 parts by weight (solid content conversion value) and copolymer latex (B) 70 to 30 parts by weight (solid content conversion value).
Consists of. When (A) is less than 30 parts by weight, moldability and shape retention are poor, and when it exceeds 70 parts by weight, fiber fixing force is poor, which is not preferable.

The copolymer latexes (A) and (B) of the present invention are produced by a known method. That is, a batch addition method, a divided addition method, a continuous addition method, a two-stage polymerization method, a power feed method and the like can be applied.

The adhesive composition of the present invention may contain an antioxidant, a filler, a flame retardant, a thickener, a surfactant, a crosslinking agent and the like.

As the carpet to which the adhesive composition of the present invention can be applied, polypropylene, polyester, nylon, acrylic,
Needle punch carpets and tufted carpets that use fibers such as wool, and are applied to automobile carpets and interior materials that require a heat molding step.

When applying or impregnating the adhesive composition of the present invention, the adhesive may be foamed or thickened to be used, and as a processing method thereof, a lick roll, a squeezing roll, a spray gun,
Immersion and the like can be mentioned. Further, in order to completely impregnate the carpet, it is preferable to squeeze the applied adhesive composition with a squeezing roll. After coating or impregnating the adhesive composition, moisture can be removed by heating to obtain a moldable carpet. Examples of the method of molding the carpet include a method of heating the carpet and molding it with a pressure roll or a press molding machine.

It should be noted that the application of the adhesive composition of the present invention to the back surface of the carpet does not hinder the backing of the thermoplastic resin film such as polyethylene by heat fusion.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples.
The present invention is in no way limited by these examples. All parts and% in the examples mean parts by weight and% by weight, unless otherwise specified.

<Preparation of Copolymer Latex (A)> Water and sodium dodecylbenzenesulfonate shown in Table 1 were mixed, and the monomer mixture shown in Table 1 was added to the mixture, and t-dodecyl was further added. Add 0.2 parts of mercaptan and emulsify. Then add 0.5 parts of potassium persulfate and add 6
Emulsion polymerization was performed at 0 ° C. The polymerization was stopped when the conversion of the monomers reached 97%. Unreacted monomers in the obtained latex were removed under reduced pressure to obtain copolymer latexes A-1 to 3 and Ai, ii, iv and V.

The polymerization of A-iii did not proceed, and a copolymer latex could not be obtained.

<Preparation of Copolymer Latex (B)> The same operation as the copolymer latex (A) was carried out except that the amounts of the monomer mixture, water and sodium dodecylbenzenesulfonate shown in Table 2 were used. Polymer latexes B-1 to 3 and B-i to ii were obtained.

Examples 1 to 3 and Comparative Examples 1 to 6 With respect to 100 parts (solid content) of the latex mixture shown in Table 3, an antioxidant (SUMILIZER S; Sumitomo Chemical Co., Ltd.)
1 part) and a surfactant (Emar 2FN; manufactured by Kao Soap Co., Ltd.) 1 part were added to obtain an adhesive composition having a solid content of 47%.

Each of the obtained adhesive compositions was foamed in a volume of 3 times with a Hobart mixer, coated on the back surface of a polypropylene / polyester blended needle punch carpet at a coating amount of 150 g / m ² , and was impregnated to the inside. After that, 130 ℃
The carpet sample obtained by drying for 5 minutes at
Moldability, shape retention and fiber fixing force were tested based on the following measuring methods.

The results are shown in Table-3.

Thermoformability; Carpet sample in oven at 180 ° C for 5
After heating for a minute, the uneven mold shown in Fig. 1 (A part: 90
And press molding (for 1 minute). This molded product was taken out of the mold and the angle of the A'section shown in FIG. 2 was measured and evaluated according to the following criteria.

○: More than 80 degrees (good) △: 75 to 80 degrees (insufficient) ×: Less than 75 degrees (poor) Shape retention: After evaluation of thermoformability, the molded product is again stored in an oven at 90 ° C for 24 hours Place

After that, it was taken out from the oven and the angle A ″ shown in FIG. 3 was measured. The change in this angle (A′−A ″) was evaluated according to the following criteria.

○: less than 10 degrees (good) △: 10 to 15 degrees (insufficient) ×: more than 15 degrees (poor) Fiber fixing force; rubbing the back side of the carpet sample with a metal piece, dropping off the adhesive and pilling the fiber Was evaluated based on the following criteria.

◯: Adhesive did not fall off or pilling was good. Δ: Adhesive fell off a little or pilling was slightly poor. X: Adhesive was dropped off (powder drop) or pilling was bad. [Effects of the present invention] The adhesive composition obtained in the present invention can simultaneously exhibit the moldability, shape retention property, and fiber fixing force required for automobile carpets, and the adhesive composition of the present invention. The product can omit the step of the two-step processing technology of lining the thermoplastic resin film, and also has the effects of simplifying the carpet manufacturing process and improving productivity.

[Brief description of drawings]

Fig. 1 is a cross-sectional view of the molding die, Fig. 2 is a cross-sectional view of the carpet after thermoforming, and Fig. 3 is a cross-section of the carpet after leaving the thermoformed carpet in an oven at 90 ° C for 24 hours. The figure is shown. B mold… B Carpet A… Angling angle (90 degrees) A ′ …… Angle after thermoforming A ″ …… Angle after standing in an oven at 90 ℃ for 24 hours

Continuation of the front page (56) Reference JP-A-63-196779 (JP, A) JP-A-62-90376 (JP, A) JP-A-63-205378 (JP, A) JP-A-61-223010 (JP , A)

Claims (1)

[Claims] 1. A composition comprising 50 to 90% by weight of α-methylstyrene, 10 to 50% by weight of acrylonitrile and 0 to 40% by weight of another copolymerizable monomer, and having a glass transition point of 110 to 160 ° C. Copolymer latex (A) having a particle diameter of 50 to 300 nm, 30 to 70 parts by weight (solid content conversion value), butadiene 10 to 90% by weight, styrene 10 to 90% by weight and other copolymerization Copolymer latex (B) 70 to 30 composed of 0 to 80% by weight of possible monomers and having a particle size of 50 to 300 nm
An adhesive composition for carpet backing, characterized by comprising parts by weight (solid content conversion value).