JPH0342580B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applied as a soft surface polyvinyl chloride sheet material for instrument panel pads, more specifically as a covering material for automobile interior parts, especially instrument panel pads. The present invention relates to a soft-surfaced polyvinyl chloride sheet material that has an excellent molding stabilizer and has a soft texture during normal vacuum forming processing.

Conventional technology and problems to be solved Conventional covering materials for instrument panel pads include ABS resin sheets.
Various materials have been used, including polyvinyl chloride (hereinafter referred to as PVC) compositions used in a molding method called the slush method. For example, (a) ABS, which has traditionally been mainly used in a molding method called the VF method, in which a convex vacuum-formed sheet is placed in an injection mold, and core material and urethane are injected and foamed. Semi-rigid ABS resin sheet material consisting of resin and other additives, (b) Fluidized or powdered PVC composition used in the slushing method, (c) Urethane paint applied to a concave mold by spraying etc. and dried. Polyurethane compositions and the like are known which are used in a molding method called a mold coal method, in which core material is injected and urethane is injected and foamed. However, molded products made of such materials do not satisfy all of the requirements of softness, cost, and mass production as instrument panel pads, and the following problems are observed. In other words, (a) above has excellent mass productivity and is the most commonly practiced method, but the resulting molded product has an extremely hard texture and
Does not satisfy the softness required for current instrument panel pads. On the other hand, (b) and (c)
In this case, the appearance is good and the softness is satisfactory, but the weight is large and the entire process is a batch type, resulting in extremely low productivity and high costs.

An object of the present invention is to provide a sheet material that is suitable for mass production and also satisfies softness and cost.

In conventional methods, it is extremely difficult for many of the PVC sheet materials used in normal plastic vacuum forming to simultaneously satisfy both the molding stability for instrument panel pads and the dimensional stability of the resulting molded product. be. From the standpoint of dimensional stability of the molded product, it is desirable that the molding temperature is as high as possible, preferably 170°C or higher; however, in the case of vacuum forming, if too high a temperature is used, the sheet may sag due to its own weight due to excessive softening. This causes difficulties in molding, such as wrinkles and tears. On the other hand, if the temperature is too low, the elongation of the sheet material will be insufficient, resulting in significant uneven thickness, and the dimensional stability of the molded product will not be obtained. Furthermore, even if the molding temperature is not such that such a problem occurs, sufficient vacuum moldability may not be obtained due to slight deviations in the molding conditions.

In this way, it is difficult to obtain high-quality instrument panel pad molded products unless PVC sheet materials suitable for vacuum forming meet extremely strict conditions.

In view of this situation, the present inventor has developed an instrument panel pad vacuum forming product that exhibits excellent dimensional stability and molding stability of an instrument panel pad molded product without using special and expensive equipment and materials. We have been studying the PVC sheet material and found that by making it into a laminated structure under specific conditions, we can combine a high plastic deformation temperature layer with a high plastic deformation temperature layer that has heat resistance strength that satisfies the harsh conditions of vacuum forming, and normal soft PVC. We have found that by applying a laminate having a structure consisting of sheet layers and having the soft PVC sheet layer as the surface layer, it is possible to simultaneously improve the quality of instrument panel pad molded products and obtain good molding stability. Note that the idea of adopting such a laminate has never been seen before.

The present invention was completed based on the above-mentioned findings, and its gist consists of a high plastic deformation temperature layer (hereinafter referred to as a heat-resistant layer) that maintains heat-resistant strength during vacuum forming, and a soft PVC sheet layer (hereinafter referred to as a normal layer). ), and the heat-resistant layer has a crosslinkable functional group such as a hydroxyl group or a carboxyl group.
An instrument that is a crosslinked soft PVC layer made by combining PVC with a crosslinking agent having two or more functional groups in the molecule that can react with hydroxyl groups or carboxyl groups, and the above-mentioned normal layer is a surface layer. This is a soft surface PVC sheet material for panel pads.

In the present invention, the composition used to form the heat-resistant layer (hereinafter referred to as a highly softening composition) includes:
The following may be mentioned.

PVC with crosslinkable functional groups (e.g. vinyl chloride and monomers with hydroxyl or carboxyl groups in the molecule (2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,
(2-hydroxypropyl acrylate, hydroxybutyl vinyl ether, methacrylic acid, monobutyl maleic acid, etc.), or hydrolysates of vinyl chloride/vinyl ester copolymers, hydrolysates of vinyl chloride/acrylic ester copolymers , acid-treated vinyl chloride/epoxy group-containing vinyl monomer copolymer, etc.) containing functional groups that can react with hydroxyl or carboxyl groups (e.g., isocyanate groups, carboxyl groups, hydroxyl groups, epoxy groups, amino groups, etc.). In combination with a crosslinking agent having two or more in the molecule (for example, tolylene diisocyanate, diphenylmethane diisocyanate, adipic acid, phthalic acid, triglycidyl isocyanurate, epoxy resin, triethyltetramine, methylolmelamine, butoxymethylmelamine, etc.), Add a common plasticizer (for example, phthalate esters such as dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, diisodecyl phthalate, dilauryl phthalate, diundecyl phthalate, and butylbenzyl phthalate are preferred), and as needed. and the usual stabilizers (dibutyltin laurate, epoxidized soybean oil,
Ba, Zn-based, etc.), fillers (calcium carbonate, etc.)
Contains pigments, flame retardants, etc.

The plastic deformation temperature of the heat-resistant layer obtained from such a composition for high softening is usually set in the range of 145 to 220°C.

In the present invention, a composition used to form a normal layer used together with a heat-resistant layer (i.e., a composition for a normal layer)
is 100 parts by weight of PVC (usually used with a number average degree of polymerization of 600 to 2200, preferably 1000 to 1700),
In the same manner, 40 to 120 parts, preferably 60 to 80 parts, of the above-mentioned plasticizer are blended, and if necessary, appropriate amounts of the above-mentioned stabilizers, fillers, pigments, flame retardants, etc. are added, and the process is carried out according to the usual method. Prepared by kneading. The plastic deformation temperature of the normal layer obtained from such a composition is usually set in the range of 130 to 180°C. The plastic deformation temperature can be appropriately set by selecting the number average degree of polymerization of PVC and the amount of plasticizer blended.

The soft PVC sheet material for instrument panel pads according to the present invention is produced by using the above-mentioned composition for high softening and composition for normal layer.
It can be manufactured using the same processing methods and conditions as sheets. For example, a layer composition is coated on a release carrier, and then a highly softening composition is coated to form a laminate, followed by melting and crosslinking, or each composition is individually formed by calendering or extrusion processing. A method may be adopted in which a sheet layer is created (in particular, these are bonded by heat welding or laminated with an adhesive), and if necessary, crosslinked.

Next, a normal thermoplastic resin solution is applied to the surface of the resulting laminate to improve its surface feel, prevent plasticizer from bleeding, and to treat the surface to gloss, and/or to the back surface to improve adhesion and prevent plasticizer from bleeding. The treatment layer may be applied by applying with a roll coater or the like. Further, at the same time as the above-mentioned surface treatment, the surface may be printed using a roll coater or the like in order to improve the appearance.

The sheet material of the present invention produced as described above is
It has a structure that requires a heat-resistant layer that maintains durability under the severe heat and high elongation conditions during vacuum forming processing to provide the dimensional stability required for instrument panel pad molded products. It is recognized that by performing vacuum forming, a molded product that is soft and has excellent dimensional stability can be obtained.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 (1) Compounding composition of the composition for the normal layer: PVC (trade name “Vinica” manufactured by Mitsubishi Monsanto Chemical Co., Ltd.)
P410'', average degree of polymerization 1400) ...100 parts diisodecyl phthalate ...80 parts dibutyltin laurate (manufactured by Akishima Chemical Co., Ltd.)
...Two-part epoxidized soybean oil (manufactured by Adeka Argus)
... 3 parts pigment ... 10 parts (2) Blending composition of highly softening composition: PVC with crosslinkable functional groups (trade name "P-100A" manufactured by Mitsubishi Monsanto Chemical Co., Ltd.) ... 50 parts PVC (average Degree of polymerization: 1700) ...50 parts diundecyl phthalate ...65 parts Ba/Zn stabilizer (manufactured by Adeka Argus)
...3 parts Epoxidized soybean oil ...3 parts Calcium carbonate ...10 parts Pigment ...10 parts Hydrogenated blocked isocyanate crosslinking agent (manufactured by Takeda Pharmaceutical Co., Ltd.) ...3 parts Highly softening composition with the above composition The composition for the normal layer and the composition for the normal layer were sequentially applied onto the release paper that had already been provided with a fine squeezing pattern to form sheet layers of 0.4 mm thickness and 0.4 mm thickness, respectively, and then heated in a heating oven at 200°C for 5 minutes. Performs melting and crosslinking reaction to create a 0.8mm thick soft
Obtain a PVC sheet laminate.

Next, vacuum forming was carried out using an infrared heating method from both the front and back sides of the laminate while varying the heating temperature arbitrarily. The physical properties of the sheet used for molding and the dimensional stability and molding stability of the resulting molded product (i.e., whether the laminate sag due to its own weight or whether the laminate is cut) were investigated, and the results are shown in Table 1 and Table 1. Shown in 2.

Comparative Example 1 Using the composition for the normal layer of Example 1, it was applied on release paper and heated and melted in the same manner as in Example 1.
A PVC sheet with a thickness of 0.8 mm was obtained, and its physical properties and moldability are also listed in Table 1.

Comparative Example 2 Table 1 also shows the physical properties and moldability of a typical ABS resin sheet used in the VF method.

Comparative Example 3 The physical properties of the skin material obtained by the slush method are also listed in Table 1.

■■■ Turtle shell [0007] ■■■ ■■■ Turtle shell [0008] ■■■

Claims (1)

[Scope of Claims] 1 It has a structure consisting of a high plastic deformation temperature layer that maintains heat resistance strength during vacuum forming and a soft polyvinyl chloride sheet layer, and the high plastic deformation temperature layer has a cross-linked hydroxyl group or carboxyl group. It is a crosslinked soft polyvinyl chloride layer made by combining polyvinyl chloride having a functional group with a crosslinking agent having two or more functional groups in the molecule that can react with a hydroxyl group or a carboxyl group, and the above-mentioned soft polyvinyl chloride sheet. A soft surface polyvinyl chloride sheet material for instrument panel pads, characterized in that the layer is a surface layer. 2. The soft surface polyvinyl chloride sheet material for an instrument panel pad according to item 1 above, wherein a thermoplastic resin treatment layer is provided on the front and/or back surface of the sheet material.