JP3280784B2 - Manufacturing method of sheet for coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a covering sheet that can be attached to the surface of a molded plastic article.
More specifically, it covers parts that may be touched by humans in automobile interiors, housings for office automation (OA) equipment and home appliances, and molded articles such as stationery, sanitary goods, daily necessities, and building material interiors. The present invention relates to a method for producing a covering sheet capable of imparting a good contact feeling and scratch resistance to a molded article.

[0002]

2. Description of the Related Art Conventionally, as such a covering sheet, for example, a sheet comprising a polyvinyl chloride layer having an embossed surface and, if necessary, a foam layer laminated on the back surface is used. Have been.

[0003] However, such a sheet using polyvinyl chloride lacks flexibility of the sheet and requires a plurality of steps in its manufacturing stage. For example, it is described in Japanese Patent Publication No. 1-14023. As described above, a covering sheet in which a polyethylene or polypropylene foam layer is laminated on the back side of a polyolefin-based thermoplastic elastomer layer whose surface is embossed has been proposed.

[0004]

[Problems to be solved by the present invention]
The sheet using the polyolefin-based elastomer described in Japanese Patent No. 14023 has a drawback that the scratch resistance is poor.

Further, in order to impart scratch resistance to a sheet, as described in JP-A-63-272547,
There is a method of coating the top coat layer in a later step, but this method requires a booth for drying the organic solvent, and has problems in working environment, pollution, and health and safety.

In addition, it is known that, for example, a co-extrusion molding method is generally employed in forming a multilayer sheet. By the way, as for the material and thickness of each layer constituting such a multilayer laminated sheet, it is required to select a material suitable for the characteristics of each layer and to set the thickness from each viewpoint of quality and cost. Therefore, for example, from the viewpoint of cost, a high-cost layer tends to be thinner, and an inexpensive layer tends to be thicker. However, when pursuing only the cost aspect, the resin melt viscosity of each layer and the difference in the flow rate etc. at the molding stage have an adverse effect, and the thickness accuracy of each layer does not come out,
In some cases, the interface is roughened, which may cause interface delamination or impair the appearance.

The present inventors have focused on the fact that the laminated sheet made of a thermoplastic urethane elastomer disclosed in JP-A-3-193343 has excellent flexibility and scratch resistance, and has considered this thermoplastic urethane. By co-extruding a layer mainly composed of an elastomer with another layer, and further using a co-extrusion method and a lamination method together, it is possible to obtain a production method which can be adapted to each purpose for different purposes in a production stage. The inventors have found that the present invention can be performed, and have completed the present invention.

That is, the present invention is directed to a method of manufacturing a covering sheet, which solves the above-mentioned problems and provides a molded article having excellent flexibility and scratch resistance and having irregularities or curved surfaces. It is possible to attach while providing a manufacturing method that is also excellent in workability and safety,
In addition, to reduce the manufacturing cost, provide a manufacturing method with as few manufacturing steps as possible, and to reduce the cost from the material side, the thickness accuracy of each layer and the adhesiveness of the interface, The purpose of the present invention is to provide a manufacturing method that does not adversely affect the quality such as the appearance.

[0009]

Means for Solving the Problems The invention according to claim 1 is characterized in that "a surface layer comprising a thermoplastic urethane elastomer as a main component, a carboxylic acid in a main chain or a side chain and an acid value of 1 is provided.
An adhesive resin layer made of a polymer or oligomer containing a compound of about 30 mgKOH / g and a base material layer made mainly of a thermoplastic resin are coextruded in a state of being stacked in this order to form a sheet-like laminate. A method for producing a coating sheet characterized by performing the method described above.

[0010] The invention according to claim 2 is that the surface layer composed mainly of the thermoplastic urethane elastomer, the adhesive resin layer, and the base material layer composed mainly of the thermoplastic resin are laminated in this order. A sheet-like laminate obtained by co-extrusion in a state, and laminating a foam layer made of a thermoplastic resin on the base layer side of the sheet-like laminate immediately after being obtained. The main point is "a method of manufacturing".

In other words, the method for producing a coating sheet according to the first and second aspects of the present invention provides a method for producing a surface layer / adhesive polymer layer / thermoplastic resin mainly composed of a specific material called thermoplastic urethane elastomer. Of the base material layer,
A sheet having a three-layer structure is manufactured, and in some cases, a foam layer is provided on the base material layer to manufacture a sheet having a four-layer structure. In the manufacture, a co-extrusion method is employed to reduce manufacturing costs. , And at the same time, produce products with excellent mechanical properties,
It aims to provide a work environment with excellent workability and safety.

The details are as follows.

In the present invention, the thermoplastic urethane elastomer used for forming the surface layer has rubber elasticity at normal temperature, and is plasticized at high temperature and can be formed into various shapes. Yes, generally a rubber component having entropy elasticity in the molecule (soft segment)
And a segment composed of urethane bonds as a molecular constraint component (hard segment) for preventing plastic deformation. In some cases, it has a crosslinked structure within the moldable range, but does not have a wide-range three-dimensional network structure.

In order to exhibit scratch resistance, the thermoplastic urethane elastomer preferably has a glass transition point (Tg) of particularly -50 to 20 ° C., and preferably has a higher molecular weight in terms of rigidity. Its weight average molecular weight is 2
The range of 3,000 to 3,000,000 is preferred. The hardness varies depending on the hardness and thickness of the base material layer and the foam layer laminated on the back surface layer.
A range of about 8 is preferred.

In the present invention, the resin constituting the base material layer may be a thermoplastic elastomer, polystyrene, an acrylic polymer, polycarbonate, polyvinyl chloride, or the like.
Examples include polyethylene, polypropylene, ABS (acrylonitrile-butadiene-styrene copolymer), modified polyphenylene oxide, polyphenylene sulfide, polyetherimide, polyetheretherketone, and ionomer. Preferably employs a thermoplastic elastomer.

For example, thermoplastic elastomers include:
Thermoplastic polyolefin-based elastomers which are excellent in moldability and cost are mentioned. Specifically, those having polypropylene as a hard segment and having ethylene as a soft segment, or those having a small amount of a diene component together with ethylene (in order of EPM) , EPDM, collectively EPR), those obtained by blending them, and those partially cross-linked by further adding an organic peroxide thereto can be used.

Further, in the presence of a titanium compound and an aluminum compound, a polypropylene-based resin,
First, the titanium-containing polyolefin obtained by prepolymerizing a propylene-based resin and propylene obtained by copolymerizing propylene and ethylene, or propylene and an α-olefin, respectively, in the presence of the titanium compound and the aluminum compound. -Ethylene or propylene-α
-An olefin copolymer is also preferably used. The polypropylene resin has a weight-average molecular weight in the range of 80,000 to 600,000.
The elution amount at 0 ° C is 20 to 80 of the total amount of the polypropylene resin.
And the approximate elution amount at 10 to 65 ° C. is 10 to 50% by weight of the total polypropylene resin amount, and 65 to 65% by weight.
1 to 15% by weight at 90 ° C, 90 to 125 ° C
Can be used such that it is in the range of 10 to 35% by weight.

The hardness of these thermoplastic polyolefin-based elastomers varies depending on the feel of the surface of the coating sheet to be obtained, but is generally preferably in the range of 50 to 98 in JIS A hardness. In addition, in order to improve the extrusion moldability and stretch moldability of the thermoplastic polyolefin-based elastomer,
Further, a polyolefin-based resin such as polypropylene or LLDPE (linear low-density polyethylene) may be contained in the base material layer.

In the present invention, as the material constituting the adhesive resin layer, a polymer or oligomer compatible with the resin constituting the surface layer and the base material layer is used. As such a resin component, a polymer or oligomer containing a compound having a functional group such as a hydroxyl group, an amide group, an epoxy group, a carboxylic acid group, or a carboxylic ester group in a main chain or a side chain is suitably used. Of these functional groups,
Those having a carboxylic acid group are particularly preferred, and the amount of the carboxylic acid is such that the acid value of the polymer or oligomer is
1-30 (mgKOH / g) is preferable. Although the molecular weight of the polymer is not particularly limited, it is generally 2,000 to 5
It is about 00,000. The softening point is preferably about 100 to 220 ° C. If the softening point is lower than this range, the heat resistance of the obtained sheet tends to deteriorate, and if it is too high, the adhesiveness tends to deteriorate.

When a polyolefin-based thermoplastic elastomer is used for the base material layer, a chlorinated polyolefin, an ionomer resin (ethylene-methacrylic acid copolymer metal salt), an acid-modified SBS (styrene-butylene- Styrene copolymer) SEBS also acid-modified
(Styrene-ethylene-butadiene-styrene copolymer) and the like are preferably used, and particularly those which themselves exhibit properties as an elastomer (for example, JIS A hardness of 50)
To about 98) is preferably used.

According to the second aspect of the present invention, the material constituting the foam layer made of a thermoplastic resin includes polyolefin resins such as polypropylene and polyethylene, and polystyrene resins such as polystyrene and styrene-maleic anhydride copolymer. And foamable resin materials such as polyurethane resin, polyvinyl chloride resin and various thermoplastic elastomer resins. In addition, the expansion ratio of these foams is preferably about 5 to 50 times, particularly preferably about 20 to 50 times, in order to exhibit cushioning properties and soft touch feeling.

The coating sheet obtained in the present invention may further contain, if necessary, materials such as a coloring agent such as a pigment and a dye, an antioxidant, an ultraviolet absorber, and a hindered amine.

As the coloring agent, pigments and dyes used in paints can be used. Examples of the pigment include titanium oxide, iron oxide, carbon black, cyanine pigment, and quinacridone pigment. Examples of the dye include an azo dye, an anthraquinone dye, an indigoid dye, and a sterbenzene dye. Further, metal powder such as aluminum flake, nickel powder, gold powder, silver powder and the like may be used as the coloring agent.
These materials are preferably fine particles as much as possible. When a coloring agent having a high hiding property is used, the amount of these coloring agents is 2 parts by weight based on 100 parts by weight of the solid content of the resin.
The range of -400 parts by weight is preferred.

In order to impart various functions to the coating sheet of the present invention, various functionalizing agents can be added.
The above various functional imparting agents, conductive material, anti-condensation agent,
Photochromic compounds, rust inhibitors and the like.

Further, in order to enhance the design of the sheet, a pattern such as printing may be applied. In this case, the printing is preferably provided on the adhesive resin layer side of the surface layer / adhesive resin layer.

In the first and second aspects of the present invention, a so-called co-extrusion molding method is employed as a method for molding a laminated sheet having a three-layer structure of a surface layer / adhesive resin layer / base material layer.
At that time, the layers are laminated such that the adhesive resin layer is located inside.

The coextrusion molding method refers to a method in which two or more extruders are used, and each extruded resin is combined into one to produce a product having a multilayer structure. The joining method by the coextrusion molding includes a foot block method, a multi-manifold method, and a multi-throttle die method. The foot block method is a method of joining by a special block attached just before entering a die, and is also called a black box method. The multi-manifold method is a method in which the number of manifolds in the die is equal to the number of layers. The multi-throttle die method is a method in which separate flows are made in a die and they are brought into close contact with each other immediately after leaving the die, and all are known methods.

Although any of these methods can be used to produce a sheet-like laminate, a multi-manifold method is preferred in order to make the thickness accuracy of each layer accurate and improve the adhesion of each layer.

Further, in the second aspect of the present invention, a lamination method is adopted as means for laminating the foam layer.

[0030] Thus, the state claim 2 as "sheet-like laminate immediately obtained co-extruded" in the invention described, the heat-fusible enough to be laminated sheet-like laminate is held Point.

In the lamination method employed as the laminating means, one or a plurality of rolls are usually used. Form fine irregularities on the surface of these rolls,
It is optional to perform embossing at the time of lamination.

[0032] In the invention of claim 2 Symbol placement, sheets lamination on a sheet extrusion molding, there is no need to especially separate steps, for example a foam sheet to form a foam layer extruded from another extruder The molded product may be used inline. When the adhesion between the base layer / foam layer or the surface layer / adhesive resin layer is poor, for example, a primer layer or an adhesive layer is provided in advance on the interface side of the foam layer, It is preferable to provide a pre-heater facing the interface just before lamination. In addition, when embossing is performed in combination with lamination, the thickness of the surface layer, the adhesive resin layer, etc., and the properties of the material such as the melting point are changed. If the appearance of the embossed shape is poor as it is, the embossed surface side It is also preferable to provide a preheating heater in the same manner as above.

The thickness of the coating sheet thus obtained varies depending on the sheet constitution, but generally, the thickness of the thermoplastic urethane elastomer layer as the surface layer is 5 to 500 μm.
m, adhesive resin layer is 5-200 μm, base material layer is 200-
It is preferable that the thickness be set to 3000 μm and the foam layer to be about 1000 to 3000 μm.

When using these covering sheets, they are shaped into a shape corresponding to the surface shape of the molded article to be affixed, and are attached to the molded article with an adhesive or shaped according to the mold cavity of the mold. However, it is possible to coat the surface of the molded product by a method such as integrally sticking to the surface of the molded product by injection molding or the like.

[0035]

According to the first and second aspects of the present invention, the surface layer, the adhesive resin layer, and the base material layer are coextruded to form a sheet-like laminate, or the sheet is foamed on the base material layer side. Since the method for producing a covering sheet is characterized in that body layers are laminated by a lamination method, each layer can be laminated and integrated in one step by using a co-extrusion method and a lamination method, thereby reducing production costs. Can be planned. Further, since it is not necessary to top coat the surface layer by casting or the like in a later step, the working environment is not deteriorated by the organic solvent. In addition, since the surface layer is mainly formed of a thermoplastic urethane elastomer, it is possible to produce a material having excellent mechanical properties such as flexibility and scratch resistance.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below.

The number of parts indicates the number of parts by weight on a solid basis.

Example 1 (Invention according to claim 1) Surface layer: thermoplastic urethane elastomer resin (Nippon Miractran Co., Ltd., E375NMAT, JIS A hardness: 75) Adhesive resin layer: acid-modified SEBS ( Asahi Kasei Kogyo Co., Ltd., Tuftec M1943, JIS A hardness 6
7, acid value 10 (mg KOH / g) Base layer: 80 parts of thermoplastic olefin elastomer resin (Mitsui Petrochemical Co., Ltd., Mirastomer 8030N) in LLDPE (melting point 120 ° C., density 0.92, Example below) The same is used for 20 parts). The above three layers are multi-manifold type dies as shown in FIG. 1 and extruders 1a (surface layer) 40φ, 1b (adhesive resin layer) 40φ, 1c (base material) Layer) Three-layer co-extrusion apparatus 2 having 50φ (each manufactured by Plastics Engineering Laboratory)
Extruded with. The resin temperature of the extruders 1a, 1b, 1c is
Performed at 190 ° C. Sheet-like laminate 4 coming out of the die
Was passed through take-off rolls 3, 3 '. The temperature of each of the take-off rolls 3, 3 'was controlled to be 40 ° C. (At this time, the foam layer was not laminated.) The thickness of each layer of the obtained covering sheet 6 was about 100 µm for the surface layer, about 30 to 50 µm for the adhesive resin layer, and about 400 µm for the base layer. 5 is an air knife.

Example 2 (Invention of Claim 1) Surface layer: thermoplastic urethane elastomer resin (manufactured by Asahi Glass Co., Ltd., PN3429, JIS A hardness: 85) Adhesive resin layer: acid-modified SEBS (Asahi Kasei (Tufftec M1943, manufactured by Kogyo Co., Ltd.) Base layer: A pellet blend of 20 parts of LLDPE in 80 parts of a thermoplastic olefin elastomer resin (Millastomer 8030N, manufactured by Mitsui Petrochemical Industries, Ltd.). A coating sheet 6 was prepared in the same manner as in Example 1.
(At this time, the foam layer was not laminated.) The thickness of each layer of the obtained covering sheet 6 was about 100 µm for the surface layer, about 30 to 50 µm for the adhesive resin layer, and about 400 µm for the base layer.

Example 3 (Invention of Claim 1) Surface layer: thermoplastic urethane elastomer resin (manufactured by Asahi Glass Co., Ltd., PN3429, JIS A hardness: 85) Adhesive resin layer: acid-modified SEBS (Asahi Kasei (Tufftec M1943, manufactured by Kogyo Co., Ltd.) Base layer: A pellet blend of 20 parts of LLDPE in 80 parts of a thermoplastic olefin elastomer resin (Millastomer 8030N, manufactured by Mitsui Petrochemical Industries, Ltd.). For the sheet-like laminate 4 extruded from the co-extrusion apparatus 2, a rubber roll having an embossed surface is used as a take-off roll 3 'in contact with the surface layer side, and the roll temperature is controlled to 50 ° C. to emboss the surface layer. Example 1 except that
A sheet for covering was prepared in the same manner as in (a foam layer was not laminated at this time). The thickness of each layer of the obtained covering sheet is such that the surface layer is 100 μm and the adhesive resin layer is 30 μm.
５０50 μm, and the substrate layer was about 400 μm.

Example 4 (Invention of Claim 2) Surface layer: thermoplastic urethane elastomer resin (manufactured by Asahi Glass Co., Ltd., PN3429, JIS A hardness: 85) Adhesive resin layer: acid-modified SEBS (Asahi Kasei (Tufftec M1943, manufactured by Kogyo Co., Ltd.) Base layer: A pellet blend of 20 parts of LLDPE in 80 parts of a thermoplastic olefin elastomer resin (Millastomer 8030N, manufactured by Mitsui Petrochemical Industries, Ltd.). Foam layer: Foamed polypropylene sheet (manufactured by Sekisui Chemical Co., Ltd., expansion ratio: 25 times, thickness: 3 mm) The above surface layer, adhesive resin layer, and base material layer were prepared in Example 1.
Extruded under the same apparatus and conditions as those described above, and on the base layer side of the extruded sheet-like laminate 4 in a molten state, the sheet-like foam layers are stacked and passed through the take-up rolls 3 and 3 ′,
Laminated. The thickness of each layer of the obtained coating sheet 6 is such that the surface layer is 100 μm and the adhesive resin layer is 30 to 50 μm.
m, the substrate layer was about 400 μm, and the foam layer was about 3 mm.

Example 5 (Invention of claim 2) Surface layer: thermoplastic urethane elastomer resin (PN3429, manufactured by Asahi Glass Co., Ltd., JIS A hardness: 85) Adhesive resin layer: acid-modified SEBS (Asahi Kasei (Tufftec M1943, manufactured by Kogyo Co., Ltd.) Base layer: A pellet blend of 20 parts of LLDPE in 80 parts of a thermoplastic olefin elastomer resin (Millastomer 8030N, manufactured by Mitsui Petrochemical Industries, Ltd.). Foam layer: Foamed polypropylene sheet (manufactured by Sekisui Chemical Co., Ltd., expansion ratio 25 times, thickness 3 mm) In the same manner as in Example 4, a foam layer was formed on the sheet laminate 4 extruded from the co-extrusion apparatus. Simultaneously with the lamination, embossing was performed on the surface layer in the same manner as in Example 3. The thickness of each layer of the obtained coating sheet 6 is 100 μm for the surface layer.
m, adhesive resin layer is 30 to 50 μm, base material layer is 400 μm
m, the foam layer was about 3 mm.

Comparative Example 1 Base layer: 80 parts of thermoplastic olefin elastomer resin (manufactured by Mitsui Petrochemical Co., Ltd., Mirastomer 8030N) and 20 parts of LLDPE were pellet-blended. The apparatus used was the same as that in FIG. 1, but a sheet corresponding to the base material layer in Example 1 was extruded using only one of the three extruders. That is, it was extruded with a 40φ extruder 1a manufactured by Plastics Engineering Laboratory (resin temperature was 210 ° C.). Further, the temperature of each of the take-off rolls 3, 3 'was controlled to be 40 ° C. The thickness of the obtained sheet was about 500 μm.

[Comparative Example 2] Base material layer: 80 parts of thermoplastic olefin elastomer resin (manufactured by Mitsui Petrochemical Industries, Ltd., Mirastomer 8030N) blended with 20 parts of LLDPE in a pellet blend. A sheet was prepared in the same manner as in Comparative Example 1, except that a rubber roll having an embossed surface was used as the take-off roll 3 ', and the roll temperature was controlled at 50 ° C. to emboss the surface. The thickness of the obtained sheet is
It was about 500 μm.

[Comparative Example 3] Base material layer: 80 parts of a thermoplastic olefin elastomer resin (manufactured by Mitsui Petrochemical Co., Ltd., Mirastomer 8030N) in which 20 parts of LLDPE was pellet-blended. Foam layer: Foamed polypropylene sheet (3 mm thick, manufactured by Sekisui Chemical Co., Ltd.) Extruded under the same apparatus and conditions as in Comparative Example 1, and the extruded sheet in a molten state is heated to 180 ° C. In a state where the foamed layers were stacked, the layers were passed through take-off rolls 3 and 3 'and laminated. The thickness of the obtained sheet was about 500 μm for the base material layer and about 3 mm for the foam layer.

Comparative Example 4 Base layer: 80 parts of a thermoplastic olefin elastomer resin (Millastomer 8030N, manufactured by Mitsui Petrochemical Industries, Ltd.) and 20 parts of LLDPE were pellet-blended. Foam layer: foamed polypropylene sheet (3 mm thick, manufactured by Sekisui Chemical Co., Ltd.) In the same manner as in Comparative Example 3, the foam layer is laminated on the sheet extruded from the co-extrusion apparatus, and at the same time, as in Comparative Example 2. Then, the surface was embossed. The thickness of the obtained sheet was about 500 μm for the base material layer and about 3 mm for the foam layer.

Table 1 shows the appearance, scratch resistance and contact feeling of the coating sheet samples in each of the examples and comparative examples. Scratch resistance was determined by a scratch strength test using a Tabers clutch tester (Toyo Seiki Seisakusho).
The load (50 g to 500 g) of the appearance change when the epidermis is scratched or torn by visual observation is represented by the following grades,
The load satisfying class 4 or higher was shown. When the contact feeling and cushioning property were good, it was indicated by ○.

[0048]

[Table 1]

The coating sheet of the present invention exhibited good scratch resistance against the sheet samples having no surface layer obtained in each of the comparative examples.

[0050]

According to the first and second aspects of the present invention, each layer can be laminated and integrated in one step by a coextrusion method or a combination of a coextrusion method and a lamination method, and the production cost can be reduced. it can. Further, since it is not necessary to top coat the surface layer by casting or the like in a later step, the working environment is not deteriorated by the organic solvent. In addition, since the surface layer is mainly formed of a thermoplastic urethane elastomer, it is possible to produce a material having excellent mechanical properties such as flexibility and scratch resistance.

Therefore, not only the productivity is excellent, but also the range of applications based on quality, workability and excellent spreadability can be expanded.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus for implementing a method for producing a covering sheet according to the first or second aspect of the present invention.

[Description of Signs ] 1a, 1b, 1c extruder 2 co-extrusion device 3, 3 ' take-off roll 4 sheet-like laminate 6 covering sheet

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI B29L 7:00 B29L 7:00 9:00 9:00 (56) References JP-A-3-193343 (JP, A) JP-A-64- 75224 (JP, A) JP-A-5-57846 (JP, A) JP-A-57-116626 (JP, A) JP-A-61-86262 (JP, A) JP-A-62-253428 (JP, A) JP-A-58-69049 (JP, A) JP-A-54-31077 (JP, U) JP-B 1-14023 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 47/00-47/96

Claims (2)

(57) [Claims] 1. An adhesive comprising a surface layer mainly composed of a thermoplastic urethane elastomer and a polymer or oligomer containing a compound having a carboxylic acid in the main chain or side chain and having an acid value of 1 to 30 mgKOH / g. A resin layer,
A method for producing a coating sheet, comprising coextruding a base material layer containing a thermoplastic resin as a main component and laminating in this order into a sheet-like laminate. 2. A sheet obtained by co-extruding a surface layer comprising a thermoplastic urethane elastomer as a main component, an adhesive resin layer, and a base material layer comprising a thermoplastic resin as a main component in a laminated state in this order. A method for producing a covering sheet, comprising: obtaining a sheet-like laminate; and laminating a foam layer made of a thermoplastic resin on the base layer side of the sheet-like laminate immediately after the sheet-like laminate.