JP2513833B2 - Interior materials for vehicles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle interior material, and more particularly to a vehicle interior material having an adhesive layer made of an aqueous polyurethane resin composition.

[Conventional technology and its problems]

Generally, a vehicle interior material is composed of a laminate of various foams used as cushioning materials and a skin material and / or a base material. Such a laminate is required to have adhesiveness, formability, tactile feel, etc. between the skin material or the base material and the foam.

Polyurethane resin-based adhesives are the mainstream as the adhesives used to manufacture the interior materials for vehicles. This is because the laminate using the polyurethane resin-based adhesive satisfies the above characteristics.

However, when using the polyurethane resin adhesive, a large amount of various organic solvents are used. Therefore, when this adhesive is used, flammability, explosiveness, toxicity, etc. become a problem, which may deteriorate the working environment and the natural environment. Therefore, a solventless polyurethane resin adhesive is provided, but this adhesive has a problem such as toxicity due to evaporation of an isocyanate monomer added as a curing agent component. Further, there are also provided an adhesive obtained by hydrating a polyurethane resin and a polyurethane elastomer with an emulsifier, and an adhesive comprising a urethane prepolymer hydrophilized by blocking a free isocyanate group with bisulfite. However, the laminate using these adhesives has not yet satisfied the above characteristics.

The object of the present invention is to provide an adhesive property under a wide range of conditions which does not cause environmental problems and which is required for an interior material for a vehicle, that is, a skin material or a base material and a foam used as a cushioning material. An object of the present invention is to provide an interior material for a vehicle, which is excellent in moldability and moldability.

[Means for solving the problem]

The vehicle interior material of the present invention is provided with an adhesive layer made of an aqueous polyurethane resin composition on at least one surface of a resin cross-linked foam, laminated with a skin material and / or a base material, and having an adhesive interface of 120 ° C. Adhesion under 0.5Kg / cm or more, 80 ℃
After 72 hours, the adhesive strength at the same temperature is 0.3 Kg / cm or more, and the moldability L / D (L is the depth of the molding die, D is the diameter of the molding die) is 0.3 or more. The skin material is obtained from a polyvinyl chloride-based sheet, a sheet made of a thermoplastic rubber elastic resin, a sheet made of a synthetic rubber, and a mixture of the polyvinyl chloride resin, the thermoplastic rubber elastic resin and the synthetic rubber. Selected from the sheet, the substrate is a sheet made of a resin mainly polypropylene,
It is selected from ABS, a sheet containing polystyrene as a main component, and these molded products.

The aqueous polyurethane resin composition comprises, for example, a polyester polyol composed of an aliphatic dibasic acid and two or more kinds of alkylene glycols, polyisocyanate, and an aqueous epoxy resin.

Resin crosslinked foam The resin crosslinked foam used in the present invention is a polyolefin resin such as a polypropylene resin or a polyethylene resin, or a polyvinyl chloride resin crosslinked foam.

The polypropylene resin used for the polypropylene resin foam is preferably a mixed resin of an ethylene-propylene copolymer containing 2 to 15% by weight of ethylene and a flexible resin. Examples of the flexible resin include linear low-density polyethylene, high-pressure low-density polyethylene, chlorinated polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-alkyl acrylate, ethylene-propylene rubber (EPR). , Plasticized soft polyvinyl chloride, internal plasticized soft polyvinyl chloride, ethylene-α
Examples thereof include olefin copolymer elastomer, styrene-butadiene rubber (SBR), and SBR hydrogenated resin. These flexible resins may be used alone or in combination of two or more. The ethylene-propylene copolymer is used in order to satisfy the heat resistance and moldability required for the vehicle interior material. Moreover, the reason why the flexible resin is used is to satisfy the flexibility and impact resistance of the interior material for a vehicle.

The polypropylene-based resin preferably contains 40 to 90% by weight of an ethylene-propylene copolymer and 10 to 60% by weight of a flexible resin. Further, a lubricant, an antioxidant, an ultraviolet absorber, a colorant, an antistatic agent, a flame retardant, a filler such as talc or calcium carbonate, a nucleating agent and other inorganic substances may be added to the polypropylene resin. .

Particularly desirable as a resin cross-linked foam using the polypropylene resin, ethylene-propylene random copolymer 40 to 85 wt%, the density is 0.885 to 0.940 g / cm ³ linear low density polyethylene 15 to 60 It is composed of a resin component containing 10 wt.
And a cross-linking index of 15 to 60% (desirably 18 to 50%). If the expansion ratio is too small, the flexibility, cushioning properties, heat insulating properties, etc., which are the characteristics of the foamed product, are insufficient and the utility value decreases. On the other hand, if the expansion ratio is too large, the mechanical strength is significantly reduced and the moldability is reduced. Further, if the degree of crosslinking is small, the surface of the foam tends to be rough, which is not aesthetically preferable. On the contrary, if the crosslinking index is large, the moldability may be deteriorated.

The cross-linking index was measured by thoroughly washing the residue obtained by immersing 0.2 g of foam pieces in tetralin at 130 ° C for 2 hours.
It is a value calculated by the following formula from the weight (W) measured after drying.

Crosslinking index = W / 0.2 x 100 (%) Polyethylene resin used for polyethylene resin foam includes high-pressure method low-density polyethylene, linear low-density polyethylene, high-density polyethylene, and ethylene-vinyl acetate copolymer. , Ethylene-acrylic acid alkyl ester copolymers, ethylene-acrylic acid alkyl ester-phthalic anhydride copolymers, and the like mainly containing ethylene can be exemplified. These may be used alone or 2
You may use it in mixture of 2 or more types. The high-pressure low-density polyethylene preferably has a density of 0.918 to 0.930 g / cm ³ and a melt index of 0.5 to 10 g / 10 min. As the linear low-density polyethylene, the density of the ethylene-α olefin copolymer is 0.885.
Is a ~0.940g / cm ^3, a melt index of 0.5~10g / 1
It is desirable to use the one for 0 minutes.

Polyvinyl chloride resin, styrene-ethylene / butylene-styrene block copolymer resin, etc. may be added to the polyethylene resin. These are usually added in an amount of 5 to 50% by weight based on the polyethylene resin. Further, an extender, a nucleating agent and other inorganic substances may be added to the polyethylene resin as in the case of the polypropylene resin.

The expansion ratio of the polyethylene resin foam is preferably 3 to 25 times. The cross-linking index is 15-60%, and 18-50.
% Is desirable. If the expansion ratio and the degree of cross-linking index are out of the above ranges, the same problems as in the case of the polypropylene resin foam may occur. The cross-linking index is a value measured by the same method as in the case of polypropylene resin foam.

The polyethylene-based resin foam is inferior in heat resistance to the polypropylene-based resin foam, but is excellent in flexibility, so that it is used as an interior material for a vehicle in a portion where tactile sensation is required.

Examples of the polyvinyl chloride resin used for the polyvinyl chloride resin foam include vinyl chloride, ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer, ethylene-vinyl acetate / vinyl chloride graft copolymer, Examples thereof include acrylic rubber / vinyl chloride graft copolymer, polyvinyl chloride / alkyl acrylate / acrylonitrile graft copolymer, and the like. The polyvinyl chloride resin is
They may be used alone or in combination of two or more.

The polyvinyl chloride resin includes a phthalate ester-based plasticizer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), Plasticizers that can be used in polyvinyl chloride resins such as chlorinated polyethylene and acrylic rubber may be added alone or in admixture of two or more. The plasticizer that can be used for the polyvinyl chloride resin has a solubility parameter value (SP value).
0.8 to 9.5 is preferable. In the polyvinyl chloride resin, the proportion of the plasticizer is preferably less than 50% by weight.

In addition, an inorganic component such as an extender or a nucleating agent may be added to the polyvinyl chloride resin as in the case of the polypropylene resin.

The expansion ratio of polyvinyl chloride resin foam is 3 to 30
It is desirable to double, more preferably 5 to 20 times. The crosslinking index is 15
~ 60%, more preferably 18-50%. If the expansion ratio and the degree of cross-linking index are out of the above ranges, the same problems as in the case of the polypropylene resin foam may occur. The cross-linking index is a value measured by the same method as in the case of polypropylene resin foam.

Polyvinyl chloride resin foam is inferior in heat resistance to polypropylene resin foam, but it is excellent in flexibility, so that it is necessary for tactile feel and high frequency welder workability. Used for wood.

Aqueous Polyurethane Resin Composition The aqueous polyurethane resin composition used in the present invention is
It is an adhesive composed of an aqueous urethane polymer and an aqueous crosslinking agent.

The water-based urethane prepolymer used in the water-based polyurethane resin composition is a urethane prepolymer composed of an active hydrogen-containing compound such as polyester, polyether or polyether ester, and polyisocyanate such as tolylene diisocyanate or hexamethylene diisocyanate. It was made water-based by the method.

The polyester is a polyvalent saturated or unsaturated carboxylic acid such as adipic acid, succinic acid, maleic anhydride, sebacic acid, or an acid anhydride thereof, and ethylene glycol, propylene glycol, tetramethylene glycol, trimethylolpropane. , 1,6-hexanediol,
Polyhydric saturated alcohols such as 1,4-butanediol,
It is a predominantly linear or branched condensation product obtained from a relatively low molecular weight polyethylene glycol, polypropylene glycol, polyalkylene glycol such as polytetramethylene glycol, or a mixture thereof. Examples of the polyether include alkylene oxides such as ethylene oxide and propylene oxide, polymerization products such as styrene oxide and epichlorohydrin, and random or block copolymers of these and addition polymers to polyhydric alcohols. Examples of the polyether ester include those obtained by adding an epoxy compound such as ethylene oxide or propylene oxide to the polyesters.

Examples of the polyisocyanate include tolylene diisocyanate and its isomers, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, araliphatic diisocyanates such as xylylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexadiene. Aliphatic diisocyanates such as methylene diisocyanate, and polyisocyanates obtained by previously adding trimethylolpropane or the like to the above diisocyanates are used alone or as a mixture.

When synthesizing the aqueous urethane prepolymer,
A phosphoric acid ester may be added to a mixture of an active hydrogen-containing compound such as polyester and polyisocyanate. When the phosphoric acid ester is added, the heat resistance of the adhesive layer is improved, and the affinity between the adhesive layer and the adherend is improved.

As a method of making the urethane prepolymer aqueous, for example, there is a method of adjusting the raw material distribution so that the molecular end of the urethane prepolymer ends with a hydroxyl group or a carboxyl group. Alternatively, the urethane prepolymer may be made aqueous by adjusting the raw material distribution so that the molecular end of the urethane prepolymer ends with an isocyanate group, and blocking this isocyanate group with a salt such as bisulfite group. in this case,
It is desirable that the urethane prepolymer contains a nonionic hydrophilic group based on an oxyethylene chain.

Examples of the aqueous crosslinking agent used in the aqueous polyurethane resin composition include aqueous epoxy resin, aqueous epoxyamines, ethanolamine and the like. These aqueous crosslinking agents may be used alone or in admixture of two or more. The water-based epoxy resin preferably has two or more epoxy groups. As such an aqueous epoxy resin, those having the following structural formulas can be exemplified.

Examples of other water-based epoxy resins include addition condensation products of bisphenol A and ipichlorohydri, glycidyl ether-based water-based epoxy resins, and epichlorohydrin-based water-based epoxy resins.

In addition to the aqueous urethane prepolymer and the aqueous crosslinking agent, an aqueous acrylic resin may be added to the aqueous urethane resin composition.

Desirable as the aqueous urethane resin composition composed of the aqueous urethane prepolymer and the aqueous crosslinking agent used in the present invention, a polyester polyol composed of the saturated carboxylic acid and alkylene glycol, and an aqueous urethane prepolymer composed of the polyisocyanate are preferable. In addition, an aqueous epoxy resin is added. In particular, as the saturated carboxylic acid, it is desirable to use an aliphatic dibasic acid such as succinic acid, adipic acid and sebacic acid. As the alkylene glycol, it is desirable to use one kind or two or more kinds selected from ethylene glycol, propylene glycol, 1,6-hexanediol, 1,4-butanediol and the like.

The aqueous urethane resin composition has a solid content of 10 to 80% by weight, preferably 25 to 50% by weight, and a solution viscosity at 25 ° C. of 1000.
It is used after adjusting to ~ 10000cps, preferably 2000-7000cps. When the solid content is less than 10% by weight, it is difficult to apply the components unless a special application device is used. On the other hand, if the solid content exceeds 80% by weight, the stability of the components may deteriorate. Further, if the solution viscosity is less than 1000 cps at 25 ℃ or less, it may be difficult to obtain a uniform adhesive layer because the aqueous epoxy resin composition may flow between the application and drying. Become. On the contrary, if the solution viscosity exceeds 10,000 cps, it becomes difficult to apply various coating methods.

Skin material As the skin material used in the present invention, a polyvinyl chloride sheet containing 50 to 90% by weight of a vinyl chloride component, a sheet made of a thermoplastic rubber elastic resin containing ethylene, propylene, etc., SBR, isoprene rubber ( IR), a sheet made of synthetic rubber such as acrylic rubber, or a sheet having a thickness of 0.1 to 2 mm obtained from the mixture of the polyvinyl chloride resin, the thermoplastic rubber elastic resin and the synthetic rubber. Alternatively, the sheet may be electro-flocked.

Substrate As the substrate used in the present invention, for example, a sheet made of a resin containing polypropylene as a main component, a sheet containing ABS or polystyrene as a main component, or a molded product thereof is used.

Vehicle Interior Material In the vehicle interior material of the present invention, as shown in FIG. 1, for example, a skin material 2 is laminated on a surface of a resin foam 1 with an adhesive layer 4 interposed therebetween. In the vehicle interior material of the present invention, as shown in FIG. 2, the resin foam 1 may be laminated on the surface of the base material layer 3 via the adhesive layer 4. Further, as shown in FIG. 3, the vehicle interior material of the present invention has a base material layer 3
The resin foam 1 may be laminated on the surface of the resin foam 1 via the adhesive layer 4, and the skin material 2 may be laminated on the surface of the resin foam 1 via the adhesive layer 4. The adhesive layer 4 is
An aqueous urethane resin composition comprising the aqueous urethane prepolymer and an aqueous crosslinking agent is cured.

In the vehicle interior material of the present invention, the adhesive strength between the resin foam and the skin material and / or the base material is 0.5 kg / cm or more at 120 ° C. Further, the adhesive force is 0.3 kg / cm or more even after being left at 80 ° C. for 72 hours at the same temperature. Therefore, the vehicle interior material of the present invention sufficiently satisfies the heat resistance and moisture resistance required for the vehicle interior material. The adhesive force is a value measured by the following method.

(1) Adhesive strength at 120 ° C Cut the vehicle interior material to a width of 2.5 cm and a length of 15 cm. Then, the skin material and the resin foam, or the resin foam and the base material are peeled off by about 7 cm to obtain a sample. This sample at 120 ℃
Put in a hot-air dryer heated to 1 and heat for 10 minutes. Quickly attach the heated sample to the heating box of a yeastlon-type tensile tester heated to 120 ° C. Then, after 5 minutes, the skin material or the base material is pulled at a pulling speed of 500 mm / min, and the absolute peel strength (X) is measured. The adhesive force can be calculated by the following formula.

Adhesion (kg / cm) = X / 2.5 (2) Adhesion at the same temperature 72 hours later at about 80 ° C Adhesion under the same temperature 120 ° C Put in a hot air dryer heated to 1 hour and heat for 72 hours. The sample is mounted in the heating box of an Eastlon tensile tester heated to 80 ° C. After 5 minutes, the skin material or the base material is pulled at a tensile strength of 200 mm / min, and the absolute peel strength (X) is measured. The adhesive force can be calculated by the following formula.

Adhesive strength (kg / cm) = X / 2.5 The vehicle interior material of the present invention is heated to a moldable temperature of 120 to 200 ° C., and is desired by a known molding method such as vacuum, compressed air, vacuum compressed air, or a press system. Is molded into the shape of. It is to be noted that a water-based urethane resin composition is applied to a base material that has been formed into a predetermined shape in advance, a vehicle interior material made of a skin material-resin foam is placed on this base material, and press-formed into the same shape as the base material. Thus, it is possible to obtain an interior material for a vehicle, which is composed of a base material-resin foam-skin material.

The vehicle interior material of the present invention exhibits good moldability and has an L / D value of 0.3 or more. The L / D value can be obtained as follows. That is, using a cylindrical mold having a diameter of 5 cm (D) and a depth of L (cm), a vehicle interior material heated to 120 to 200 ° C. is vacuum formed. From the maximum value of the depth L when there was no breakage in any part of the obtained molded product and it was possible to mold without difficulty,
Calculate the L / D value.

The vehicle interior material of the present invention is, for example, a dashboard,
Used for door trim, molded ceiling, seat back, rear quarter trim, center pillar pad, etc.

Manufacturing of vehicle interior material First, surface treatment such as corona discharge treatment or flame treatment is performed so that the surface of the resin foam exhibits a wettability index of 35 to 72 dyne / cm. If the wetting index is less than 35 dyne / cm,
The foam and the water-based urethane resin composition do not fit well, and it becomes difficult to uniformly apply the water-based urethane resin composition. On the other hand, when the wetting index exceeds 72 dyne / cm, the moisture resistance and water resistance of the resin foam surface deteriorate.

Next, the water-based urethane resin composition, on the surface of the resin foam subjected to the surface treatment, by a known coating method such as a gravure coating method and a roll coating method, 10 to 200 g / m 2.
² (Wet) Apply. Then, the water content of the aqueous urethane resin composition is removed by using hot air at 60 to 120 ° C. or a heating means such as an infrared heater or a radiant heater. The heating means may be used in combination.

A skin material and / or a base material is laminated on the resin foam coated with the aqueous urethane resin composition. It is desirable to heat the skin material and / or the base material to 50 to 140 ° C. in advance. These skin materials and / or base materials are pressure-bonded at a pressure of 0.3 to 200 kg / cm ² .

When the laminate obtained from the skin material-resin foam, the resin foam-base material, or the skin material-resin foam-base material thus obtained is aged for 24 hours or more, the vehicle interior of the present invention The material can be obtained.

〔The invention's effect〕

In the present invention, without causing environmental problems, the characteristics required for vehicle interior materials, that is, a skin material or a base material,
It is possible to obtain an interior material for a vehicle which has excellent adhesion and moldability under a wide range of conditions with a foam used as a cushioning material.

〔Example〕

Example 1 Using a resin mixture of 80 parts by weight of an ethylene-propylene copolymer and 20 parts by weight of a linear low density polyethylene (L-LDPE), a plate-like foam having an expansion ratio of 18 times and a degree of crosslinking index of 40%. Got 90 parts by weight of polyvinyl chloride resin and AB
A 0.4 mm-thick sheet-like skin material made of a resin mixture with 10 parts by weight of S resin was laminated to obtain a laminate. This laminated body,
A thickness equivalent to L / D 0.6 that has been molded into the desired shape beforehand
It was molded along a 3 mm ABS resin base material and simultaneously laminated by adhesion to obtain a vehicle interior material.

As the adhesive, a polyester polyol composed of alkylene glycol in which neopentyl glycol, 1,6-hexanediol and 1,4-butanediol are mixed in a ratio of 1: 5.2: 2.5 mol% with respect to adipic acid, and 2, An aqueous urethane resin composition having a viscosity of 6000 cps (25 ° C.) obtained by adding a glycidyl ether-based aqueous epoxy resin to a urethane prepolymer composed of 2,4-trimethylhexamethylene diisocyanate was used.

The peeling strength between the skin material and the foam, and the foam and the base material, and the moldability of the obtained vehicle interior material were examined.

Example 2 80 parts by weight of ethylene-propylene copolymer and L-LDPE20
Using a resin mixture with parts by weight, a plate-like foam having a foaming ratio of 30 times and a crosslinking degree index of 35% was obtained. Add 100 parts by weight of polyvinyl chloride resin and diisodecyl phthalate (D
A sheet-like skin material having a thickness of 0.8 mm and made of a resin mixture with 40 parts by weight of IDP) was laminated to obtain a laminate. This laminate is preformed into a desired shape and has an L / D of 0.7 and a thickness of 3.
An interior material for a vehicle was obtained by molding along with a 0 mm wood hardboard base material and at the same time bonding and laminating.

 The same adhesive as in Example 1 was used.

The peeling strength and moldability of the obtained vehicle interior material were examined in the same manner as in Example 1.

Example 3 A resin mixture of 100 parts by weight of polyvinyl chloride and 40 parts by weight of DIDP was used to obtain a plate-like foam having an expansion ratio of 13 times and a degree of crosslinking index of 35%. A laminate obtained by laminating the same skin material as in Example 2 on this foam is molded along an ABS resin substrate having a thickness of 1.5 mm and having an L / D of 0.6, which is molded in a desired shape in advance, and is bonded at the same time. The layers were laminated to obtain a vehicle interior material.

 The same adhesive as in Example 1 was used.

The peeling strength and moldability of the obtained vehicle interior material were examined in the same manner as in Example 1.

Comparative Example 1 The resin foam, skin material and base material used in Example 1 were
Laminated using an adhesive consisting of a modified vinyl resin (trade name: CEL10, manufactured by Konishi Co., Ltd.) and a curing agent (trade name: curing agent M, manufactured by Konishi Co., Ltd.) with a viscosity of 35000 cps (25 ° C) Then, an interior material for a vehicle was obtained.

With respect to this vehicle interior material, the peel strength and moldability were examined in the same manner as in Example 1.

Comparative Example 2 A polyurethane foam (trade name: Elastron E-37, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and ethanol mono were used as the base material composed of the resin foam, the skin material, and the ABS resin used in Example 2. Using an adhesive composed of ethylamine and a viscosity of 500 cps (25 ° C), the layers were laminated to obtain a vehicle interior material.

With respect to this vehicle interior material, the peel strength and moldability were examined in the same manner as in Example 2.

Comparative Example 3 The resin foam, skin material and base material used in Example 3 were
Polyurethane resin (brand name: EF-30, manufactured by Waterchem Co., Ltd.) and water-based epoxy resin (Waterchem Co., Ltd.)
Was manufactured by using an adhesive having a viscosity of 10000 cps (25 ° C.), and an interior material for a vehicle was obtained.

With respect to this vehicle interior material, the peel strength and moldability were examined in the same manner as in Example 3.

The results of Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1.

[Brief description of drawings]

1, 2 and 3 are longitudinal sectional views of the interior material for a vehicle of the present invention. 1 ... Resin foam, 2 ... Skin material, 3 ... Base material layer, 4 ...
… Adhesive layer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 62-185707 (JP, A) JP 59-113016 (JP, A) JP 63-319135 (JP, A)

Claims (2)

(57) [Claims] 1. A resin crosslinked foam on at least one surface thereof,
An adhesive layer made of an aqueous polyurethane resin composition is provided,
Laminated with skin material and / or base material, 12 of its adhesive interface
Adhesive strength at 0 ° C is 0.5 Kg / cm or more, adhesive strength at 80 ° C after 72 hours at the same temperature is 0.3 Kg / cm or more, and moldability
L / D (L is the depth of the molding die, D is the diameter of the molding die) is 0.3
That is, the skin material is a polyvinyl chloride sheet,
A sheet made of a thermoplastic rubber elastic resin, a sheet made of a synthetic rubber, and a sheet obtained from a mixture of the polyvinyl chloride resin, the thermoplastic rubber elastic resin and the synthetic rubber, and the base material is polypropylene. An interior material for a vehicle, which is selected from a sheet composed mainly of resin, a sheet composed mainly of ABS and polystyrene, and a molded product thereof. 2. The aqueous polyurethane resin composition comprises a polyester polyotel composed of an aliphatic dibasic acid and two or more kinds of alkylene glycols, a polyisocyanate, and an aqueous epoxy resin. Interior materials for vehicles.