JPH11228710A - Acrylic resin film for decorative board - Google Patents

Abstract

(57) [Abstract] [Problem] To provide an acrylic resin film for a decorative board without printing omission. SOLUTION: At least one film surface has a height of 5 mm.
Acrylic resin film for decorative boards with a thickness of 500 μm or less without irregularities of μm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to weather resistance and printability used for surface skins for printing on interior and exterior materials for vehicles, home appliances, MDF (medium density fiber board), interior and exterior materials for building materials, and the like. The present invention relates to an acrylic resin film for decorative boards which has excellent properties.

[0002]

2. Description of the Related Art Acrylic resin films are made of window frames, wallpaper, polycarbonate,
Used for surface protection of vinyl chloride resin products. As the acrylic resin film used for these, those described in JP-A-63-77963 and the like are known.

[0003]

However, these acrylic resin films have a problem that printing loss occurs when printing is performed on the surface. The present inventors have analyzed this phenomenon and found that 5 μm
It has been found that if there are irregularities of m or more, printing omissions will occur there, and by eliminating irregularities of 5 μm or more on the film surface, printing omissions will not occur and acrylic resin films for decorative boards will be excellent in printability. Was obtained. Therefore, an object of the present invention is to provide an acrylic resin film for a decorative board without printing omission.

[0004]

The present invention resides in an acrylic resin film for a decorative plate having a thickness of 500 μm or less, characterized in that at least one surface of the film has no unevenness having a height of 5 μm or more.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The acrylic resin forming the acrylic resin film for decorative boards of the present invention is not particularly limited as long as it is composed of a polymer containing methyl methacrylate as a main component, but 50% by weight of methyl methacrylate is used. As described above, for example, methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate ,
C1-C1 such as 2-ethylhexyl (meth) acrylate
(8) alkyl (meth) acrylates, styrenes such as styrene and α-methylstyrene, maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, and copolymerizable copolymers such as maleic acid, maleic anhydride and acrylonitrile. Any acrylic resin containing less than 50% by weight of the monomer having a heavy bond may be used. For better transparency and appearance, the content of methyl methacrylate is more preferably 70% by weight or more. Further, depending on the purpose, two or more monomers may be used.

The acrylic resin has a glass transition temperature (hereinafter, abbreviated as Tg) of 5 in order to impart flexibility to the film and to improve handleability and processability.
It is preferably composed of an acrylic resin matrix (A) containing methyl methacrylate at 0 ° C or higher and 150 ° C or lower as a main component and a crosslinked elastic body (B).

[0007] The acrylic resin matrix (A) containing methyl methacrylate as a main component contains not less than 50% by weight of methyl methacrylate, for example, methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylate. )
C1-C8 alkyl (meth) acrylates such as butyl acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, styrene, 50% by weight of monomers having a copolymerizable double bond such as styrenes such as α-methylstyrene, maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, and maleic acid, maleic anhydride and acrylonitrile. A resin having a Tg of 50 ° C. or higher and 1
The monomers are selected so as to be in the range of 50 ° C. or less. Two or more monomers may be used depending on the purpose.

On the other hand, the crosslinked elastic body (B) may be any crosslinked elastic rubber such as an acrylic, butadiene, polyolefin, silicone, or fluorine-based rubber. Rubber is most preferred.

Examples of the acrylic crosslinked elastic rubber include, for example, alkyl acrylates having 1 to 8 carbon atoms, 80 to 99.9.
15% by weight, monomer 15 having one copolymerizable double bond
% By weight, a polyfunctional monomer having two or more copolymerizable double bonds in the range of 0.1 to 5% by weight, and a material selected so that Tg is 0 ° C. or less is a transparent film. It is preferable from the viewpoint of physical properties such as properties and elongation.

Further, the crosslinked elastic rubber is coated with a rubber layer (B-
1) As an outer layer, one or more graft layers (B-2) comprising 20 to 80% by weight of a monomer having a double bond copolymerizable with 20 to 80% by weight of an alkyl methacrylate having 1 to 4 carbon atoms. The crosslinked elastic body having a core-shell structure having the structure (1) is particularly preferable because it reduces stress whitening of the film.

Further, in order to improve the transparency and impact strength, it is necessary to use not less than 50% by weight of methyl methacrylate, for example, methyl acrylate, ethyl (meth) acrylate,
1-8 carbon atoms such as propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate Alkyl (meth) acrylates, styrenes such as styrene and α-methylstyrene, N-phenylmaleimide and N-
Maleimides such as cyclohexylmaleimide, and maleic acid, maleic anhydride, and monomers having copolymerizable double bonds such as acrylonitrile were selected such that Tg was 20 ° C. or higher in a range of less than 50% by weight. An inner layer polymer (B-3) composed of one or more layers, and one or more rubber layers (B-1) having a Tg of 0 ° C. or lower on the outside of the inner layer polymer;
Further, a crosslinked elastic body having one or more graft layers (B-2) in the outer layer is preferable.

The acrylic resin forming the decorative board film of the present invention is preferably composed of 10 to 90% by weight of an acrylic resin matrix (A) and 10 to 90% by weight of a crosslinked elastic body (B). This is preferred from the viewpoints of elongation, transparency and workability.

Known additives such as stabilizers, lubricants, processing aids, plasticizers, impact-resistant aids, coloring agents, and ultraviolet absorbers can be added to the acrylic resin according to the purpose.

The irregularities on the film surface specified in the present invention are as follows:
The height is 5 μm or more. This height is measured, for example, with a surface shape measuring microscope (VF-750, manufactured by Keyence Corporation).
When the measurement is performed in step 0), the height difference is 5 μm or more when measuring 200 μm between scanning line distances.

In order to eliminate the printing omission on the acrylic resin film for decorative board, which is an object of the present invention, it is necessary that at least one surface of the film to be printed has no unevenness having a height of 5 μm or more. It is more preferable that unevenness of 5 μm or more does not exist on both surfaces, because the appearance of the film is good. Irregularities of less than 5 μm may be present.

The method for producing the acrylic resin film for decorative board of the present invention is not particularly limited, and any method may be used. However, any foreign matter present in the acrylic resin, which mainly causes irregularities generated on the film surface, is used. And a method of smoothing at least one film surface during film formation.

First, as a method of removing foreign matter which causes irregularities, a method of filtering with a filter during melt extrusion is effective. When the acrylic resin as a raw material is polymerized by emulsion polymerization, filtering the obtained latex with a filter is also an effective means.

Next, as a method for smoothing the surface of the film, a melt extrusion method such as a T-die method or an inflation method, or a method of smoothing a mirror-finished roll when an acrylic resin is formed into a film by a calendar method or the like. There is a method of eliminating irregularities on one surface on which a surface is transferred, and a method of eliminating irregularities on both surfaces of a film by sandwiching the film between two mirror-finished rolls.

When the thickness of the acrylic resin film for a decorative plate of the present invention exceeds 500 μm, the rigidity is increased, which is not preferable as a protective film. Considering the design of the surface, the thickness of the acrylic resin film is 50-30.
A range of 0 μm is preferred.

[0020]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In addition, the measuring method used for evaluation is as follows. In the description, “parts” indicates parts by weight.

[Number of missing prints] Gravure printing was performed on an acrylic resin film, and the number of missing prints in a 20 m ² film was measured.

[Number of Surface Irregularities] Using a surface shape measuring microscope (VF-7500, manufactured by KEYENCE CORPORATION), the surface shape was measured at a scanning line distance of 200 μm for a portion having an optical distortion in a film of 20 m ² , and the height was measured. The number having a height difference of 5 μm or more was measured.

[Production Example of Acrylic Resin] Production method of acrylic resin matrix (M-1 to 3) 0.2 part of octyl mercaptan, 0.3 part of 1,1-di-t-butylperoxy-2-methylcyclohexane with respect to 100 parts of the monomer mixture shown in Table 1. 0.02 part of a copolymer of methacrylic acid and sodium 2-sulfoethyl methacrylate, 0.15 part of sodium sulfate, 200 parts of pure water
The part was polymerized at 80 ° C. under a nitrogen atmosphere to obtain an acrylic resin matrix (M-1 to 3).

[0024]

[Table 1]

2. Production Method of Crosslinked Elastic Body (K-1) The following ratio of raw materials was charged into a reaction vessel, and the polymerization was completed while stirring at 50 ° C. for 4 hours under a nitrogen atmosphere.
An elastic latex was obtained. Butyl acrylate (BA) 77 parts Styrene 22.7 parts Allyl methacrylate 0.3 parts Dioctyl sodium sulfosuccinate 2.0 parts Deionized water 300 parts Potassium persulfate 0.3 parts Disodium phosphate dodecahydrate 0.5 parts Sodium hydrogen phosphate dihydrate 0.3 parts

100 parts (as solid content) of the obtained elastic latex are placed in a reaction vessel, and the mixture is purged with nitrogen while stirring. Then, the temperature is raised to 80 ° C., 0.125 part of sodium formaldehyde sulfoxylate, sulfuric acid Ferric iron 5pp
m, disodium ethylenediaminetetraacetate 15 ppm,
After adding an aqueous solution composed of 2 parts of pure water, a mixture composed of 60 parts of methyl methacrylate, 0.05 part of n-octyl mercaptan, and 0.125 part of t-butyl hydroperoxide was added for 2 hours while maintaining the temperature at 80 ° C. After the dropwise addition, the mixture was kept for 2 hours to obtain a crosslinked elastic body (K-1).

3. Production method of acrylic resin (P-1, 2) In a polymerization vessel equipped with a cooler, 250 parts of ion-exchanged water, 2 parts of ester soda salt of sulfosuccinic acid, 0.05 part of sodium formaldehyde sulfoxylate, and 1 part of ferric sulfate
0 ppm, disodium ethylenediaminetetraacetate 30p
After stirring under nitrogen, 1.6 parts of methyl methacrylate, 8 parts of butyl acrylate, 0.4 part of 1,3-butylene methacrylate and 0.1 part of allyl methacrylate were added.
And a mixture consisting of 0.04 parts of cumene hydroperoxide. After raising the temperature to 80 ° C., the reaction was continued for 60 minutes to complete the polymerization of the rubber layer 1.

Subsequently, 1.5 parts of methyl methacrylate, 22.5 parts of butyl acrylate, 1.0 part of 1,3-butylene methacrylate, 0.25 part of allyl methacrylate,
A monomer mixture consisting of 0.04 parts of cumene hydroperoxide was added over 60 minutes and polymerized to obtain two rubber layers. Subsequently, methyl methacrylate 5 was used as the graft layer 1.
Part, 5 parts of butyl acrylate, 0.1 part of allyl methacrylate and 0.01 part of cumene hydroperoxide, and finally, to simultaneously form an acrylic resin matrix and a graft layer, 52.25 parts of methyl methacrylate, butyl Acrylic resin (P-4, 5) by reacting a monomer mixture consisting of 2.75 parts of acrylate
Latex was obtained. Open this latex with an aperture of 50 μm
After filtration through a filter of
1) The product obtained by salting out without filtration with a filter was defined as (P-2).

[Examples 1 to 5] and [Comparative Examples 1 and 2] The resins shown in the production examples of the acrylic resin were used alone or in Table 2
And melt-kneaded at a cylinder temperature of 200 to 260 ° C. and a die temperature of 250 ° C. using a 40 mmφ screw type extruder (L / D = 26) to form pellets. The obtained pellets were dried at 80 ° C. for a day and a night. The filters shown in Table 2 were provided in a 115 mmφ extruder, and the printing omission and the number of irregularities of a 0.2 mm thick film obtained using a T-die were evaluated. .

Example 6 A film obtained by forming a film in the same manner as in Comparative Example 1 except that the film immediately after leaving the T-die was sandwiched between two mirror-finished rolls and the mirror surface was transferred to the film. The print omission and the number of irregularities of the 2 mm thick film were evaluated. Table 2 collectively shows the resin composition of each example, the aperture of the filter used, and the evaluation results.

[0031]

[Table 2]

[0032]

The acrylic film for decorative board of the present invention is
It has excellent transparency and weather resistance, and has no printing omissions.
It is suitable as an interior or exterior material of a vehicle, or as a skin of a printed surface of an electric appliance or the like.

Claims (1)

[Claims] 1. A height of at least one of the film surfaces is 5.
500 μm thickness characterized by no irregularities of more than μm
The following acrylic resin films for decorative boards.