JPH04166334A - acrylic film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an acrylic film with excellent scratch resistance.

[Prior Art] Acrylic resins, especially methyl methacrylate polymers, have a beautiful appearance and excellent weather resistance, and occupy a unique position among general-purpose resins, and are used in a wide range of molding materials such as injection molded products and extrusion molded products. is used as.

On the other hand, since such polymers are hard and brittle, when used for special purposes such as films, it is desired to impart elasticity to them, and various studies have been made to date.

Examples of methods for imparting elasticity include a method of blending elastic bodies, a method of simply copolymerizing elastic body components, and a method of graft polymerizing a resin component to an elastic body to form a multistage polymer.

By molding the above various acrylic polymers into films and laminating them onto other base materials, products with excellent weather resistance and stain resistance can be obtained.

[Problems to be Solved by the Invention] However, a major practical drawback of common acrylic films containing elastic bodies is that they have poor scratch resistance. In particular, when laminated with polycarbonate or vinyl chloride resin and used for outdoor purposes, the film surface may become dirty due to airborne particles or rain.
Damage to the surface when wiping off this dirt is a major practical problem.

[Means to solve the problem]

Therefore, in view of the current situation, the present inventors conducted extensive studies to develop an acrylic film with excellent scratch resistance.The inventors of the present invention found that by providing a resin layer containing a specific acrylic methacrylate as the main component, the scratch resistance could be improved. The present invention was achieved by discovering that an excellent acrylic film can be obtained.

That is, the present invention uses a resin having a Rockwell hardness of 90 or more on the M scale, the main component of which is alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, on at least one side of the acrylic film layer (A) containing an elastic body. It is an acrylic film having a layer (A).

The acrylic film layer (A) containing an elastic body constituting the acrylic film of the present invention is an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms, such as alkyl acrylate, ethyl acrylate, etc. , a homopolymer mainly composed of propyl methacrylate, butyl acrylate, octyl acrylate, etc., or an alkyl methacrylate whose alkyl group has 1 to 4 carbon atoms, such as methyl methacrylate, ethyl methacrylate, Examples include copolymers containing at least one of propyl methacrylate, butyl methacrylate, etc. as a dominant component and at least one other comonomer copolymerizable with these as a minor component, or mixtures of these homopolymers and copolymers. . These homopolymers and copolymers can be obtained by various polymerization methods such as suspension polymerization, emulsion polymerization, or bulk polymerization.

Further, a resin layer (B) having a Rockwell hardness of 90 or more on the M scale, which is mainly composed of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms used in the present invention.
Examples include the aforementioned alkyl methacrylate homopolymers or copolymers, or mixtures of these homopolymers and copolymers; however, in order to obtain good scratch resistance, A
It is necessary that the Rockwell hardness measured by STMD-785 is 90 or more on the M scale.

Further, a rubber component may be added to the resin layer containing alkyl methacrylate as a main component, as long as the Rockwell hardness does not become less than 90 on the M scale.

For the production of the acrylic film of the present invention, a coextrusion method using a plurality of extruders and a feed block die or multi-frame hold die is desirable, but production by lamination or coating is also useful.

The acrylic film of the present invention may contain heat or light stabilizers, ultraviolet absorbers, processing aids, lubricants, etc., as required.
Organic or inorganic matting agents can be added.

In addition, other resin components can be added to the acrylic film layer or resin layer as long as they do not impair the purpose of the present invention. In particular, vinylidene fluoride resin is effective in improving film elongation and dissolution resistance. be.

When laminating the acrylic film of the present invention on another base material, it is natural to laminate at least one side of the resin layer on the opposite side.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

The scratch resistance was evaluated by press-bonding the obtained film onto a 3□ thick polycarbonate plate at 120°C so that the film layer (A) and the polycarbonate plate were in contact with each other.
Evaluation was made by a falling sand abrasion test (ASTMD673), and the difference between the haze value of the plate before the test and the haze value of the plate after 50 g of sand had fallen was shown as the Δ haze value.

Example After drying the resin shown in Table 1 in a box dryer for a day and night, Hibet HBsOO1 was prepared using a uniaxial extruder with a diameter of 40 mm,
Acribet MF (Experiment 1) or Acribet MD (
Experiment 2) was conducted using a 25 mm diameter single screw extruder.
The film was extruded from a multi-manifold type T-die for two layers in two widths to obtain a film with a total thickness of 50 μm, with the Hypet 888001 layer being 40 μm and the Acryvet MD or MS layer being 10 μm.

When the obtained film was evaluated, it was found that △ in Experiment 1
The haze value was 6%, and the Δ haze value in Experiment 2 was 5%.

Table 1 Comparative Example A 50 μm thick film made only of Hibet HBSOOI was press-bonded to a polycarbonate plate in the same manner as in the example, and then evaluated in the same manner, and the Δ haze value was 16%.

Further, when trying to form a film of 50 μm in thickness from each of Acryvet MF and MD, the film was brittle and cracked, and could not be used as a film.

[Effects of the Invention] The film of the present invention has better scratch resistance than general acrylic films, and exhibits excellent industrial effects.

Claims (1)

[Claims] 1) On at least one side of the acrylic film layer (A) containing an elastic body, a resin layer (B ) acrylic film.