JPH04268313A - Production of synthetic resin molding excellent in mar resistance - Google Patents

Abstract

PURPOSE:To obtain a molding having high surface hardness and excellent mar resistance and adhesion between a surface protective film and a substrate by injecting a thermoplastic resin into a mold to which a film or sheet comprising an acrylic composition has been applied to integrate the resin with the film or sheet. CONSTITUTION:A cured film or sheet 1 made from an acrylic composition containing 10-60wt.%, based on the entire acrylic compound, epoxy acrylate resin of the formula (wherein R is H or lower alkyl; R' is H or CH3; and n is 0-20) is applied to the cavity of a mold 2, and a thermoplastic resin 3 (e.g. polycarbonate) is injected into the cavity of the mold 2 from an injection machine through a nozzle 4 to integrate the cured film 1 with the polycarbonate 3 or the like. A molding having high surface hardness, markedly excellent mar resistance, improved weathering resistance and excellent adhesion between the protection film and the substrate can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for imparting excellent scratch resistance to the surface of thermoplastic resin molded articles.

0002

BACKGROUND OF THE INVENTION Hitherto, laminated molded products have been known in which the surface layer and the inner layer are made of different types of thermoplastic resins to improve rigidity, surface hardness, heat resistance, and impact resistance. For example, as disclosed in Japanese Patent Publication No. 1-22151, the surface layer is made of biaxially oriented polymethyl methacrylate, the inner layer is made of polycarbonate, and the two are integrally bonded together. Polymethyl methacrylate and polycarbonate sheets are commonly used as vehicle glazing materials. However, although polymethyl methacrylate has excellent rigidity, surface hardness, and weather resistance, it has low impact resistance and heat resistance. Polycarbonate has excellent impact resistance and flame resistance, but has low rigidity and surface hardness. Biaxial orientation of polymethyl methacrylate improves impact resistance, but
Weather resistance and hardness remain unchanged. Therefore, by taking advantage of the characteristics of both, the surface layer is made of biaxially oriented polymethyl methacrylate, which provides rigidity, surface hardness, and weather resistance, and the inner layer is made of polycarbonate, which provides impact resistance. and exhibits heat resistance. However, when actually manufacturing this product, it is biaxially oriented molding of an ultra-high molecular weight polymethyl methacrylate homopolymer with a weight average molecular weight of 1 million or more, so it is difficult to melt when heated. The viscosity is so high that it cannot generally be formed by extrusion and must be formed by rolling.

On the other hand, in order to improve the surface characteristics of polycarbonate molded articles, various attempts have been made to apply paint to the surface of the molded article to form a protective film. For example, there is a method in which a thermosetting melamine resin paint is applied and a protective film is formed by thermosetting. However, these methods of forming a protective film by heat curing require processing of the molded product under harsh conditions of high temperature and long time during curing, and this process
There is an increased risk that the bonate molded article will lose its original good mechanical properties. Furthermore, problems arise in the adhesion between the polycarbonate base material and the protective film and in the durability of the protective film itself. Regarding molding technology, one type of injection molding involves punching out a film that has been hard-coated or printed on one side in advance into the desired shape, placing it in an injection mold, and molding the core material. , methods for integrating them have also been reported. However, this technology is only a general theory and does not provide solutions for specific products. In other words, it does not propose specific measures for a certain product.

0004

SUMMARY OF THE INVENTION An object of the present invention is to improve the drawbacks of the prior art and to improve the scratch resistance, hardness, and weather resistance of polycarbonate surfaces using an injection mold. Furthermore, it is an object of the present invention to provide a method for manufacturing a composite polycarbonate molded article having excellent adhesion between a surface protective film and a base material.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the purpose, the gist of the present invention is (1) to provide a method for integrally molding by attaching it to an injection mold. , an epoxy acrylate resin having the structure of formula I (where R represents H or a lower alkyl group, and R' represents H
Or it shows CH3. n=an integer from 0 to 20. ) A cured film or sheet made of an acrylic composition containing 10 to 60% by weight of the total acrylic compound is attached to a mold in advance, and then a thermoplastic resin is injected into the mold to inject the thermoplastic resin into the mold. A method for producing a synthetic resin molded article with excellent scratch resistance, which is characterized by being integrated with a cured film or sheet.

[Chemical formula 3] (2) In the method of integrally molding the resin by installing it in an injection mold, the epoxy acrylate resin having the structure of formula I (wherein, R represents H or a lower alkyl group, and R' represents H or C
Indicates H3. n=an integer from 0 to 20. ) is prepared by forming a cured film or sheet made of an acrylic composition containing 10 to 60% by weight of the total acrylic compound on a thermoplastic resin film or sheet, and then attaching it to a mold in advance, and then heating it separately. A method for producing a synthetic resin molded article with excellent scratch resistance, characterized by injecting a plastic resin into a mold and integrating the two.

[C4]

The present invention will be explained in detail below. In the present invention, polycarbonate (PC), an alloy containing 50% or more of PC, and polymethyl methacrylate (PMMA) are suitable as materials for the injection molded product due to the purpose of use. Polycarbonate is a commonly used material with a weight average molecular weight of 100,000 or less, and although it has a high softening temperature, its melt viscosity rapidly decreases once it reaches the softening temperature, making it suitable for injection molding materials. . General injection molding grade polymethyl methacrylate can be used. However, any thermoplastic resin may be used as long as it can achieve the purpose of the present invention. The reason we chose polycarbonate in particular is that, as mentioned above, it has excellent impact resistance, flame resistance, tensile strength, and creep properties, and furthermore, it has a high thermal deformation temperature depending on the magnitude of the load. This is because it does not change, has good low-temperature properties, and has excellent transparency and weather resistance. That is, polycarbonate is used because it is transparent, lightweight, has excellent mechanical properties, and is easily processed. Also,
Polymethyl methacrylate also has excellent transparency and weather resistance.

Next, the present invention is characterized by an acrylic composition containing 10 to 60% by weight of the entire acrylic compound of an epoxy acrylate resin having the structure of formula I as a scratch resistance imparting material. The reason is that a cured film or sheet is used. This acrylic composition also has transparency, and is expected to be used in glazing, signboards, etc. by combining it with PC and PMMA, which have excellent transparency. In addition, examples of acrylic compounds other than epoxy acrylate resin include trimethylolpropane tri(meth)acrylate and trimethylolethanely(meth)acrylate.
Poly(meth)acrylates of trihydric or higher aliphatic polyhydric alcohols such as dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexaacrylate, etc.
It can be fried. As the solvent, methyl ethyl ketone, ethyl acetate, ethyl cellosolve acetate, etc. are used. To form a film or sheet, the formula I
An acrylic composition consisting of 10 to 60% by weight of an epoxy acrylate resin having the structure and the remainder being an acrylic compound other than epoxy acrylate is blended with 3 to 90% by weight of a solvent to prepare a composition solution. In this case, the concentration of these solvents may be appropriately selected so as to facilitate the formation of a film. Applying this composition solution onto a glass plate or plastic plate,
After curing by irradiation with ultraviolet rays or electron beams, the cured film or sheet is peeled off for use. Alternatively, the surface can be hard coated by applying a solution of the above-mentioned composition onto a film or sheet made of a thermoplastic resin, such as polycarbonate or polymethyl methacrylate, and curing it in the same manner. A resin film or sheet which has been subjected to the coating treatment is produced and applied to the present invention.

Accordingly, the first method for manufacturing the product of the present invention is to attach a cured film 1 in the form of a film or sheet manufactured by the above-mentioned method to the cavity of a mold 2 in advance, as shown in FIG. A thermoplastic resin such as polycarbonate 3 is injected from an injection molding machine into the cavity of the mold 2 through a nozzle 4, and the cured film 1 is integrally joined to the polycarbonate 3. It is. Furthermore, the second method for producing the product of the present invention is to use a thermoplastic resin as a third film or sheet that is adhesive to the injection molded product, as shown in FIG.
For example, a film or sheet 7 made of polycarbonate, on which the above-mentioned cured film 6 is formed and hard coated, is installed in advance in the cavity of the mold 2. Separately, thermoplastic resins such as polycarbonate 3
A hard coated film or sheet 7 is injected into the cavity of a mold 2 and integrally joined to a polycarbonate 3.

[0009]

[Example] Example 1 A: Epoxy acrylate resin having the structure of formula I = 35% by weight B: Methyl ethyl ketone = 30% by weight C: DPHA (dipentaerythritol hexaacrylate) = 35% by weight % of 1-hydroxycyclohexyl phenyl ketone as a sensitizer to a mixture consisting of 3% by weight of (A+B).
Added. A mixed composition consisting of the above was applied on a glass plate to form a uniform film, then dried and cured by ultraviolet irradiation, and the film was peeled off from the glass plate to obtain a film with a thickness of 20 μm. This film is 160x160x3
(thickness) and injected polycarbonate into a mold having a flat plate shape. Polycarbonate: Mitsubishi Kasei Valex 7022 Injection molding machine: Toshiba Machine IS-100E Inlet side (C1) (C2) (C3) Outlet side (C4
) Injection molding conditions: Cylinder temperature 230℃⇒260
℃⇒280℃⇒280℃ Injection pressure: 1400kg/cm2 Mold temperature
: 70℃ Molding cycle: Injection 10 seconds, holding pressure
3 seconds, cooling 20 seconds Adhesion between film and polycarbonate: 100/100 according to goblin test/JIS K-5400. Surface scratch resistance: Even when rubbed with steel wool, there were no scratches at all. Example 2 After applying the mixed solution of the formulation of Example 1 to one side of a 100 μm thick polycarbonate film, a curing treatment was performed in the same manner. This treated polycarbonate film was attached to a mold having a flat plate shape of 160×160×3 (thickness), and polycarbonate was injected into the mold. Polycarbonate: Mitsubishi Kasei Valex 7022 Injection molding machine: Toshiba Machine IS-100E Inlet side (C1) (C2) (C3) Outlet side (C4
) Injection molding conditions: Cylinder temperature 230℃⇒260
℃⇒290℃⇒290℃ Injection pressure: 1500kg/cm2 Mold temperature
: 90℃ Molding cycle: Injection 10 seconds, holding pressure
3 seconds, cooling 25 seconds Hard coat material adhesion: Goban test/JIS K
-100/100 at 5400. Surface scratch resistance: Even when rubbed with steel wool, there were no scratches at all.

0010

[Effects of the Invention] As described above, the polycarbonate molded product can be easily applied on the production line by mounting it on an injection mold, and is made by combining the above-mentioned cured film. Its surface has high hardness, excellent scratch resistance, excellent weather resistance, and also excellent adhesion between the cured film and polycarbonate. Therefore, molded products with excellent surface properties can be produced at low cost while retaining the properties inherent to plastics, such as light weight, toughness, and transparency, and are extremely advantageous in practical use as automobile parts.

[0011]

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an injection mold according to the present invention.

FIG. 2 is a sectional view of a sheet that has been hard coated in advance.

[Explanation of symbols]

1 Cured film, sheet, 2 Mold, 3 Polycarbonate (thermoplastic resin), 4 Nozzle, 5 Polycarbonate, 6 Cured film, 7 Hard coat treated sheet .

Claims (2)

[Claims] [Claim 1] In a method of integrally molding an epoxy acrylic resin having a structure of formula I,
resin (where R represents H or a lower alkyl group, R'
represents H or CH3. n=an integer from 0 to 20. )
A cured film or sheet made of an acrylic composition containing 10 to 60% by weight of the total acrylic compound is attached to a mold in advance, and then a thermoplastic resin is injected into the mold to cure the thermoplastic resin. A method for producing a synthetic resin molded article with excellent scratch resistance, which is characterized by being integrated with a film or sheet. [Chemical formula 1] [Claim 2] In a method of integrally molding an epoxy acrylic resin having a structure of formula I,
resin (where R represents H or a lower alkyl group, R'
represents H or CH3. n=an integer from 0 to 20. )
A cured film or sheet made of an acrylic composition containing 10 to 60% by weight of the total acrylic compound is formed on a thermoplastic resin film or sheet, and then a thermoplastic resin film or sheet is mounted in advance on a mold. A method for producing a synthetic resin molded product with excellent scratch resistance, characterized by injecting resin into a mold and integrating the two. [Chemical 2]