JPH0131775B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method of manufacturing a sheet used for automobile interior materials and the like.

(Prior Art) Conventionally, soft vinyl chloride resin or a blend of soft vinyl chloride resin and ABS resin has been used for automobile interior materials, particularly sheets used for instrument panel pads and door trim skins. These materials had the following drawbacks. That is, fogging of the window due to volatilization of the plasticizer contained in the material, deterioration and discoloration due to ultraviolet rays of sunlight incident through the window, deterioration and discoloration due to thermal decomposition, and,
In particular, this is due to the poor cold resistance of vinyl chloride resin, which causes embrittlement and fracture in cold weather.

Therefore, sheets made of polyolefin resin have recently been used. Although this sheet could overcome the above-mentioned drawbacks, there was a problem with surface performance.
That is, the surface is easily scratched, the surface is too shiny, giving a poor appearance, the surface is rough and feels unpleasant, and the surface is attacked by hydrocarbon solvents.

(Objective of the Invention) The present invention has been made based on the above circumstances, and its object is to maintain flexibility and elasticity without containing plasticizers, have high light resistance, heat resistance, and cold resistance, and be scratch resistant. It is an object of the present invention to provide a sheet manufacturing method capable of obtaining a sheet having excellent surface properties such as strength, surface gloss, and surface texture.

(Structure of the Invention) The gist of the present invention is to mold a sheet from a raw material containing a polyolefin resin and a partially crosslinked ethylene-α olefin copolymer, and to coat the surface of the sheet with a saturated polyester resin, an acrylic acid ester, etc. The present invention provides a method for manufacturing a sheet, which comprises applying a reactive paint containing a resin and an isocyanate resin.

Polyolefin Resin As the polyolefin resin, for example, a homopolymer of ethylene or propylene, or a copolymer of ethylene or propylene with a small amount of a polymerizable monomer is used.

When adding a surface pattern during sheet processing as described below, in order to prevent the pattern from disappearing during subsequent thermoforming such as vacuum forming, use a propylene homopolymer (polypropylene) or propylene with a carbon number as polyolefin resin. Preferably, a copolymer with 2 to 10 olefins is used.

In addition, in order to facilitate the sheet processing described below,
Melt flow rate (230℃, 2.16Kg pressure) is 0.1
~20 g/10 min, preferably 1 to 14 g/10 min of polyolefin resin.

Partially crosslinked ethylene-α-olefin copolymer Partially cross-linked ethylene-α-olefin copolymer includes, for example, a binary copolymer of ethylene and an α-olefin having 3 to 14 carbon atoms, or a copolymer of ethylene and α-olefin having 3 to 14 carbon atoms; A terpolymer copolymerized with α-olefin and various polyene compounds is used.

As a partially crosslinked ethylene-α olefin copolymer, in order to impart impact resistance at low temperatures,
The molar ratio of ethylene and α-olefin is 40/60 to 80/20, preferably 50/50 to 70/30.

Partial crosslinking of the ethylene-α-olefin copolymer is carried out by adding an oxidizing agent to increase the active oxygen concentration to the polymer from 0.01 to 0.04 mol/Kg, preferably from 0.02 to
This is achieved by thermoforming it into pellets, for example, in the range of 0.03 mol/Kg. During this partial crosslinking, polar groups such as -C=O, -COOH, and -OH are simultaneously created near the partially crosslinked portion.

Sheet processing Polyolefin resin and partially cross-linked ethylene
The α-olefin copolymer is preferably 80/20
Mix in a weight ratio of ~10/90, more preferably 70/30 to 25/75.

The above-mentioned mixed raw material may be mixed with a precipitating agent, a heat stabilizer, a flame retardant, an antistatic agent, a process oil, etc., if necessary.

The above mixed material is molded into a sheet using a plastic processing machine such as an extrusion molding machine equipped with a T-die or a calendar molding machine. Incidentally, at the same time as the above-mentioned molding, a pattern (drawing) may be added to the sheet surface.

The sheet processed as described above has strong physical properties and excellent heat resistance, cold resistance, and light resistance. That is, the continuous usable heat resistance temperature is 120 to 130℃, the cold embrittlement temperature is -30 to -60℃ (depending on the physical properties and ratio of the polyolefin resin to be mixed), and the light resistance test using Sunshear Infedometer, Black panel
Strength retention rate is 70% or more after 1000 hours at 83℃ (equivalent to 5 years of continuous outdoor exposure). Furthermore, it has excellent press and vacuum formability. Furthermore, flexibility and elasticity can be ensured without the need for plasticizers.

Reactive Paint A reactive paint contains a saturated polyester resin, an acrylic ester resin, and an isocyanate resin, to which a solvent and, if necessary, a pigment are added.

In the above components, the acrylic ester resin is used to impart surface properties such as scratch strength to the sheet, and includes, for example, polymethyl methacrylate, poly2-ethylhexyl methacrylate, polyisobutyl acrylate, polyethyl acrylate, or polybutyl acrylate. A single substance or a copolymer of two or more of them can be used. As described later, the isocyanate resin is used to ensure the adhesion of the reactive paint to the sheet by bonding with the polar groups on the sheet side, and may be hexamethylene diisocyanate, isophorone diisocyanate, or diphenylmethane added with water. Diisocyanates or derivatives thereof are used.
The saturated polyester resin is for maintaining the bond between the acrylic acid ester resin and the isocyanate resin, and polyethylene terephthalate, polybutylene terephthalate, or derivatives thereof are used.

Furthermore, when the above-described saturated polyester resin, acrylic ester resin, and isocyanate resin are combined, a polyurethane resin is basically produced. The reaction may also produce polyurea resins and polyisocyanate resins.

In order to ensure the effects of the above-mentioned components, it is preferable to use a blending ratio of 2 to 8 parts (by weight, same hereinafter) of the saturated polyester resin, 8 to 2 parts of the acrylic ester resin, and 0.1 to 5.5 parts of the isocyanate resin.

It is preferable to use an aliphatic isocyanate resin.

Application of Reactive Paint The above-mentioned reactive paint is applied to the surface of the sheet formed as described above. This coating can be done using general coating methods such as gravure coater, roll coater,
This can be done using a knife coater, screen coater, spray, etc.

During this coating, the isocyanate resin in the reactive paint binds the polar groups on the sheet surface and the unsaturated groups at the molecular ends, so a strong coating film (surface treatment layer) is formed.

Conventionally, a technique is known in which a reactive paint is applied by applying corona discharge to the surface of an olefin resin, but according to the present invention, there is no need to perform a treatment such as the above-mentioned corona discharge prior to painting. Superior to conventional methods.

Furthermore, the surface performance of the sheet can be improved by the coating film. That is, the sheet has excellent physical properties as mentioned above, but on the other hand, because it is made of polyolefin, it has poor scratch strength and is easily attacked by hydrocarbon solvents, etc., and has shortcomings in surface performance. This drawback can be solved by coating. Also,
The coating film allows surface gloss, surface feel, etc. to be adjusted to optimal conditions. The above-mentioned coating film can be stretched during thermoforming and has excellent moldability.

Example 1 (See Figures 1 and 2) 100 parts of a partially crosslinked ethylene-α olefin copolymer was mixed with 100 parts of a polypropylene resin, and the mixture was molded into a 0.5 mm thick mixture using an extrusion molding machine equipped with a T die. While extruding the sheet 1, one side of the sheet was squeezed using a squeezing roll. On the other hand, 4 parts of saturated polyester resin, 9 parts of acrylic ester resin, 2 parts of isocyanate resin, 1 part of pigment, and 84 parts of toluene as a solvent.
A reactive paint is obtained by mixing the parts. Then, 50 g/m ² of this reactive paint was applied to the apertured surface of the sheet 1 using a gravure coater to form a coating film 2. Next, 25 g/m ² of adhesive was applied to the back surface of the sheet 1 using a gravure coater to form an adhesive layer 3. This sheet 1 was heated with an infrared heater until the surface temperature reached 160° C., and then molded into the shape of an instrument panel pad using a vacuum forming method. Next, a core material 4 made of steel was set in a foam mold, and after the sheet 1 was set, semi-rigid urethane 5 was injected and foamed to create an instrument panel pad.

The surface of the instrument panel pad obtained by the above method had an appropriate level of gloss and was smooth to the touch without being rough. moreover,
When I rubbed the surface with my fingernail, it did not cause any scratches, and it was confirmed that the scratch strength was high. In addition, the surface was wiped vigorously with a flannel cloth soaked in industrial gasoline, but
There were no abnormalities. Furthermore, a test piece was cut out and tested using a light resistance tester at a black panel temperature of 83°C.
Although the test was conducted for 1000 hours, there were no changes in physical properties or appearance that would cause any practical problems.

Example 2 (See Figures 3 and 4) 150 parts of partially crosslinked ethylene-α olefin copolymer was mixed with 100 parts of polypropylene resin, and the mixture was molded to a thickness of 0.4 mm using an extrusion molding machine equipped with a T die. At the same time, extrude sheet 11 of 3mm thick
Double-expanded polypropylene foam 15 was laminated to create a laminate skin material 16. on the other hand,
3 parts of saturated polyester resin, 7 parts of acrylic ester resin, 1 part of isocyanate resin, 1 part of pigment,
A reactive paint was obtained by mixing 88 parts of toluene as a solvent, and 50 g/m ² of this reactive paint was applied onto the surface of the sheet 11 using a gravure coater to form a coating film 12. Next, the above laminate skin material 1
6 was heated with an infrared heater until the surface temperature reached 160°C, and then vacuum formed using a female mold 17 with a diaphragm on the surface using a female vacuum forming method. The material 14 was set in the descending plug 18, and this was pushed into the molded laminate skin material 16 to integrate it, thereby creating a door trim.

The door trim obtained by the above method was tested in the same manner as in Example 1, and the same results as in Example 1 were obtained.

Example 3 (See Figures 5 and 6) 170 parts of partially crosslinked ethylene-α olefin copolymer was mixed with 100 parts of polypropylene resin, and a sheet 21 with a thickness of 0.3 mm was formed using a calendar molding machine. At the same time as the fabrication process, a squeeze was applied to one side using a squeeze roll. On the other hand, saturated polyester resin 8
1 part, 2 parts of acrylic ester resin, 5.0 parts of isocyanate resin, 1 part of pigment, 84 parts of toluene as solvent
A reactive paint was obtained by mixing the two parts. Then, 80 g/m ² of this reactive paint was applied to the constricted surface of the sheet 21 by spraying to form a coating film 22. Next, 25 g/m ² of adhesive was applied to the back surface of the sheet 21 using a gravure coater to form an adhesive layer 23. Next, a hard board 24 with a thickness of 2 mm,
The PVC-impregnated urethane foam 25 with a thickness of 2 mm and the above-mentioned sheet 21 were stacked in this order. Then, a welder portion 27 serving as decoration and fixing is formed by ultrasonic vibration, and the end portion of the sheet 21 is attached to the hard board 24.
I wrapped it around the back of the door and fixed it with adhesive to create a door trim.

The door trim obtained by the above method was tested in the same manner as in Example 1, and the same results as in Example 1 were obtained.

(Effects of the Invention) As explained above, according to the method of the present invention, by forming a sheet from a raw material containing a polyolefin resin and a partially crosslinked ethylene-α olefin copolymer, the sheet can be formed without using a plasticizer. A sheet with strong physical properties and excellent heat, cold, and light resistance can be obtained. Moreover, by applying a reactive paint containing saturated polyester resin, acrylic acid ester resin, and isocyanate resin to the surface of the sheet to form a coating film, it improves scratch strength and resistance to hydrocarbon solvents. In addition, it is possible to adjust the surface gloss, feel, etc., and improve surface performance. Also,
A strong coating film can be formed with a simple painting process. Furthermore, the coating film formed according to the present invention is
It can be stretched during thermoforming and has excellent moldability.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a sheet made by the first embodiment of the method of the present invention, Fig. 2 is a cross-sectional view of an instrument panel pad using the same sheet, and Fig. 3 is a second embodiment of the method of the present invention. FIG. 4 is a cross-sectional view showing the process of creating a door trim using the same sheet, FIG. 5 is a cross-sectional view of a sheet created by the third embodiment of the method of the present invention, and FIG. is a sectional view of a door trim using the same sheet. 1, 11, 21... sheet, 2, 12, 22...
...paint film.

Claims (1)

[Claims] 1. A sheet is formed from a raw material containing a polyolefin resin and a partially crosslinked ethylene-α olefin copolymer, and a saturated polyester resin, an acrylic ester resin, and an isocyanate resin are coated on the surface of this sheet. A method for producing a sheet, comprising applying a reactive paint containing. 2. The sheet material according to claim 1, wherein a polyolefin resin and a partially crosslinked ethylene-α olefin copolymer are blended in a weight ratio of 80/20 to 10/90. A method of manufacturing sheets. 3. According to claim 1, the sheet raw material is characterized in that a polyolefin resin and a partially crosslinked ethylene-α olefin copolymer are blended in a weight ratio of 70/30 to 25/75. A method of manufacturing sheets. 4. The sheet manufacturing method according to claim 1, wherein a polypropylene resin is used as the polyolefin resin of the sheet raw material. 5 In the reactive paint, 2 to 8 parts of saturated polyester resin (parts by weight, the same applies hereinafter), 8 to 2 parts of acrylic ester resin, and 0.1 part of isocyanate resin.
2. The method for producing a sheet according to claim 1, wherein the blending ratio is 5.5 parts to 5.5 parts.