JP2009227833A - Film for decorative sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environment-friendly film for a decorative sheet, which increases a ratio of plant-based raw materials while maintaining performance equal to the conventional olefinic decorative sheet. <P>SOLUTION: The film for a decorative sheet includes 20-50 mass% of a polyolefin resin having an initial bending modulus of 700-2,000 MPa and 40-80 mass% of an aliphatic polyester resin at least containing a polylactic acid, and has a thickness of 50-100 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a film for a decorative sheet used for building interior materials, surfaces of joinery, surface materials of home appliances, and the like, and particularly as a decorative plate by being bonded to wooden boards, inorganic boards, metal plates, etc. It is related with the film for decorative sheets used.

  Conventionally, vinyl chloride sheets have been widely used as decorative sheets used for building interior materials, surfaces of joinery, cover materials for home appliances, and the like. However, it is said that vinyl chloride resin generates hydrogen chloride gas during incineration, causing acid rain and dioxins, and there is also a pre-out problem of plasticizer added to the sheet, from the viewpoint of environmental problems. Olefin-based decorative sheets are widely used.

However, in order to reduce carbon dioxide emissions, which are a cause of global warming, the movement to convert raw materials from petroleum resources to plant-derived resources has become active, including polylactic acid. Biomass plastic development is progressing, and applications are being developed in various fields. (For example, see Patent Document 1.)
JP 2006-321988 A

However, polylactic acid has problems such as low heat resistance, easy hydrolysis, low impact strength, and poor adhesion, and it has been difficult to develop in the field of decorative sheets that particularly require durability.
This invention is made | formed in view of the said situation, and it aims at providing the film for environmentally friendly decorative sheets which raised plant origin, maintaining the performance similar to the conventional olefin type decorative sheet.

The gist of the present invention aimed at solving the above problems is as follows.
[1] A polyolefin resin having an initial flexural modulus in a range of 700 MPa to 2000 MPa is contained in a proportion of 20 to 50% by mass, and an aliphatic polyester resin containing at least polylactic acid is contained in a proportion of 40 to 80% by mass, and a thickness of 50 to 50%. A film for decorative sheets, which is a film in the range of 100 μm.
[2] It has a sea-island structure in which the aliphatic polyester resin containing at least the polylactic acid is dispersed as islands in the sea of the polyolefin resin, and the polyolefin resin is 70% of the total surface area of the decorative sheet film. The film for decorative sheets according to [1], wherein the film is exposed in an area of at least%.
[3] The film for a decorative sheet according to [1] or [2], wherein the aliphatic polyester resin containing at least the polylactic acid has a dispersion average particle size in the film thickness direction of 20 μm or less.
[4] The decorative sheet film according to any one of the above [1] to [3], wherein the film contains a pigment and is colored.
[5] The film for a decorative sheet according to any one of [1] to [4], wherein a compatibilizing agent is contained.

  According to the decorative sheet film of the present invention, by making a film containing a polyolefin resin and an aliphatic polyester resin containing polylactic acid, the performance equivalent to that of a conventional olefin-based decorative sheet can be exhibited. -Friendly film for decorative sheets can be provided.

  The film for decorative sheets which is embodiment of this invention is demonstrated in detail below.

The film for decorative sheets of the present invention is a film having a thickness in the range of 50 to 100 μm, including a polyolefin resin having an initial flexural modulus of 700 MPa to 2000 MPa and an aliphatic polyester resin containing at least polylactic acid. The film for decorative sheets of the present invention has a so-called sea-island structure in which islands of aliphatic polyester resin are dispersed in a polyolefin resin sea. Further, the decorative sheet film of the present invention may contain a pigment for coloring, may contain a compatibilizer, and may contain various additives.
Hereinafter, the component of the film for decorative sheets of this invention and the manufacturing method of the film for decorative sheets are demonstrated sequentially.

In the present invention, the aliphatic polyester resin containing at least polylactic acid is mainly a polylactic acid resin alone, a copolymer of polylactic acid and another monomer (hereinafter referred to as polylactic acid copolymer), or polylactic acid and another monomer. Any of a mixture with an aliphatic polyester (hereinafter referred to as a polylactic acid mixed resin).
Polylactic acid is used for the purpose of reducing the environmental burden by converting the resin into biomass. Polylactic acid is currently widely developed as an aliphatic polyester mainly synthesized from plant-derived raw materials. Polylactic acid is a homopolymer of either L-lactic acid or D-lactic acid, a random copolymer of L-lactic acid and D-lactic acid, a block copolymer of L-lactic acid and D-lactic acid, or a mixture of two or more thereof. The crystallinity can be controlled by the enantiomeric ratio and the method (random, block, graft, etc.) in which these isomers are copolymerized, and can be appropriately selected in the present invention.

Specifically, like other resins, the crystallinity of polylactic acid is maximized when only one of the enantiomers of lactic acid is present in a polymerized form in the resin. Therefore, L-lactic acid or D-lactic acid homopolymer has the highest crystallinity and is suitable for applications requiring rigidity and heat resistance. In addition, when the impact resistance of the homopolymer becomes a problem or when a certain degree of flexibility is required, a block copolymer, a random copolymer, or a mixture thereof can be appropriately selected as necessary.
The polylactic acid resin is obtained by polymerizing the above homopolymer, random copolymer, or block copolymer alone or in combination of two or more thereof. In the present invention, it is preferable to use a polylactic acid resin as the aliphatic polyester resin because the environmental load can be most reduced.

Moreover, a polylactic acid copolymer can be used as an aliphatic polyester resin containing the polylactic acid of the present invention. The polylactic acid copolymer is obtained by copolymerizing polylactic acid and monomers constituting various other aliphatic polyesters.
As monomers constituting the aliphatic polyester, in addition to lactic acid (L-lactic acid, D-lactic acid, DL-lactic acid), glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvalid Herbic acid, aliphatic hydroxycarboxylic acids such as 6-hydroxycaproic acid, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 3- Aliphatic dihydric alcohols such as methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, succinic acid, Succinic acid, malonic acid, gluta Acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanedioic acid, phenyl succinic acid, can be exemplified aliphatic dibasic acids such as 1,4-phenylene acetate. A polylactic acid copolymer can be formed by copolymerizing at least one or two or more of these monomers with a combination of polylactic acid. The content of polylactic acid in the polylactic acid copolymer is preferably 80% by mass or more and 100% by mass or less, and more preferably 95% by mass or more and 100% by mass or less.

Moreover, you may use polylactic acid mixed resin as aliphatic polyester resin containing the polylactic acid of this invention. The polylactic acid mixed resin is a mixture of polylactic acid and other various aliphatic polyesters.
Aliphatic polyesters include lactic acid (L-lactic acid, D-lactic acid, DL-lactic acid), glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 6- Aliphatic hydroxycarboxylic acids such as hydroxycaproic acid, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1, Aliphatic dihydric alcohols such as 5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, succinic acid, succinic acid, malon Acid, glutaric acid, adipic acid, Polymerized by combining at least one or two or more aliphatic dibasic acids such as melicic acid, suberic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, phenylsuccinic acid, 1,4-phenylenediacetic acid Can be used. A polylactic acid mixed resin can be constituted by mixing polylactic acid with such an aliphatic polyester. The content of polylactic acid in the polylactic acid mixed resin is preferably 50% by mass or more and 100% by mass or less, and more preferably 80% by mass or more and 100% by mass or less.

Also, one or more aliphatics selected from polyglycolic acid, polyethylene oxalate, polybutylene oxalate, polycaprolactone, polyneopentyl glycol oxalate, polyethylene succinate, polybutylene succinate, polyhydroxybutyric acid, etc. Polyester may be appropriately mixed with polylactic acid resin, polylactic acid copolymer or polylactic acid mixed resin. In addition, these aliphatic polyesters may have a polymer chain extended by a binder such as diisocyanate, a small amount of an aliphatic polyhydric alcohol such as glycerin, and a fatty acid such as butanetetracarboxylic acid. A group polybasic acid and a polyhydric alcohol may be used in the coexistence.
In addition, some of the aliphatic hydroxycarboxylic acids, aliphatic dihydric alcohols, and aliphatic dibasic acids are being researched and developed to change raw materials to plant-derived materials. It is more desirable to use it.

  The proportion of the aliphatic polyester resin containing polylactic acid in the decorative sheet film of the present invention is preferably in the range of 40% by mass to 80% by mass, and more preferably in the range of 50% by mass to 70% by mass. If it is less than 40% by mass, the content of biomass plastic is lowered, and the effect of reducing carbon dioxide emissions is limited, which is not preferable. On the other hand, if it exceeds 80% by mass, a sea-island structure in which the polyolefin resin is the sea and the aliphatic polyester is the island cannot be obtained, and each physical property is greatly deteriorated.

  Next, the polyolefin resin in the present invention complements the drawbacks of low heat resistance, which is a weak point of aliphatic polyester resins mainly containing polylactic acid, ease of hydrolysis, weak impact strength, and poor adhesion. Used for purposes.

  Examples of the polyolefin resin used in the present invention include polyethylene, polypropylene, polybutene, polyisoprene, ethylene-propylene copolymer, ethylene-α olefin copolymer, propylene-α olefin copolymer, and these polyolefins are unsaturated dicarboxylic acid and / or Or it can select suitably from the acid-modified polyolefin resin etc. which were modified | denatured with the acid anhydride, and what was mixed single or multiple types may be sufficient.

  The proportion of the polyolefin resin in the decorative sheet film of the present invention is preferably in the range of 20% by mass to 50% by mass, and more preferably in the range of 30% by mass to 45% by mass. If it is less than 20% by mass, the biomass plastic content is decreased, and the effect of reducing carbon dioxide emission is limited, which is not preferable. On the other hand, if it exceeds 50% by mass, a sea-island structure in which the polyolefin resin is the sea and the aliphatic polyester is the island cannot be obtained, and each physical property is greatly deteriorated.

The polyolefin resin preferably has an initial flexural modulus in the range of 700 to 2000 MPa, more preferably in the range of 800 to 1500.
When the pressure is less than 700 MPa, the elastic modulus of the decorative sheet film is lowered, and when printing is performed on the surface of the decorative sheet film, it is not preferable. On the other hand, if it exceeds 2000 MPa, the elastic modulus of the decorative sheet film becomes excessive, and the crystallization of the polyolefin resin proceeds, making it impossible to form a film.

Moreover, it is desirable to use a compatibilizing agent in order to improve the physical properties by favorably dispersing the aliphatic polyester resin containing polylactic acid to the polyolefin resin to form a sea-island structure.
As the compatibilizing agent, an acid-modified polyolefin resin obtained by modifying a polyolefin with an unsaturated dicarboxylic acid and / or an acid anhydride thereof, or a block copolymer having a nonpolar part and a polar part are often used. It is important that the added compatibilizer is present between the polyolefin resin serving as the sea and the aliphatic polyester resin containing polylactic acid serving as the island to improve the adhesion at the interface.
The content of the compatibilizer in the decorative sheet film is preferably 1 to 10% by mass, and more preferably 3 to 5% by mass.

The film for decorative sheet of the present invention has a phase structure in which a dispersed phase is dispersed in a continuous phase when a polyolefin resin is a continuous phase (sea) and an aliphatic polyester resin containing polylactic acid is a dispersion (island). have.
Moreover, in the film for decorative sheets of this invention, the dispersion average particle diameter of the dispersed phase of the thickness direction of a film is 20 micrometers or less. By setting the dispersion average particle size to 20 μm or less, the dispersed phase can be uniformly dispersed in the continuous phase, and thereby the content of the aliphatic polyester resin containing polylactic acid can be increased.

  The dispersion average particle size of the dispersed phase of the dispersed phase in the film thickness direction is, for example, a TEM / STEM transmission electron such as TEM / STEM after dyeing a film sample cut perpendicular to the film flow direction by a known method such as ruthenium oxide. This is obtained by a method of performing observation and measurement a plurality of times with a microscope and obtaining an average.

  In the decorative sheet film of the present invention, the polyolefin resin is preferably exposed in an area of 70% or more of the total surface area of the decorative sheet film. Since the continuous phase made of polyolefin resin is widely exposed on the film surface, the aliphatic polyester resin containing polylactic acid is relatively concealed. Low heat resistance, which is a disadvantage of polylactic acid, and easily hydrolyzable In addition, low impact strength can be improved. Moreover, the adhesiveness with respect to another base material can be improved because polyolefin resin is exposed widely.

  The exposed area of the polyolefin resin is determined by a method of observing the film surface dyed by a known method such as ruthenium oxide dyeing with a transmission electron microscope such as TEM / STEM. When the exposed area of the polyolefin resin is close to 70% and it is difficult to measure, the X-ray microanalyzer (EPMA) is used for measurement several times, and the exposed area is obtained from the ratio.

  Examples of the pigment include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, mica and other pearl pigments.

  Also, as various additives, various fillers, heat stabilizers, acid neutralizers, ultraviolet absorbers, light stabilizers, carboxyl group endblockers, antistatic agents, lubricants, nucleating agents, flame retardants as necessary Further, an antiblocking agent, a gloss adjusting agent, and the like can be added. Among these additives, as fillers, talc, non-swelling mica, swelling mica, swollen mica subjected to ion exchange, calcium carbonate, bentonite, organically modified montmorillonite, magnesium hydroxide, flastonite, silica, alumina, Magnesium oxide, calcium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, potassium titanate, boron nitride , Graphite, glass fiber, carbon fiber, cotton fiber, hemp fiber, kenaf fiber, hemp fiber, jute fiber, banana fiber, coconut fiber, cellulose fiber, fine powder, main powder, bamboo powder, cellulose powder, rice husk powder, fruit straw powder , Ta Park proteins, such as starch and the like.

  As heat stabilizers, hindered phenols, sulfurs, phosphoruss, etc., acid neutralizers, stearic acid metal salts, hydrotalcite, etc., UV absorbers, benzotriazoles, benzoates, benzophenones, triazines, etc. Hindered amines as light stabilizers, carbodiimides, glycidyl esters, etc. as carboxyl end-capping agents, halogen flame retardants, phosphorus flame retardants, chlorine flame retardants, etc. as flame retardants, hydrocarbons as lubricants Lubricants, fatty acids, higher alcohols, fatty acid amides, metal soaps, esters, fluorines, etc. Nucleating agents include carboxylate metal salts, sorbitol, phosphate ester metal salts, etc. It is common to use additives in any combination.

  These various additives may be tens of parts by mass or less when the total of the polyolefin resin, the aliphatic polyester resin containing polylactic acid, the pigment, and the compatibilizer is 100 parts by mass.

Further, the thickness of the decorative sheet film is preferably 50 to 100 μm, and more preferably 70 to 90 μm. If the thickness is less than 50 μm, the decorative sheet film is likely to be stretched. For example, when printing is performed on the decorative sheet film, the decorative sheet film is excessively stretched and printing becomes difficult.
Moreover, when thickness exceeds 100 micrometers, since whitening will occur when the film for decorative sheets is bent, it is unpreferable.

Next, the manufacturing method of the film for decorative sheets of the above-mentioned this invention is demonstrated.
The production method of the present invention includes a step of mixing at least a polyolefin resin and an aliphatic polyester resin containing polylactic acid to obtain a compound, and a step of extruding the compound as a colored film.

  The method of kneading the polyolefin resin and the aliphatic polyester resin containing polylactic acid is not particularly limited, but a method of obtaining a compound by mixing and pelletizing with a biaxial extrusion kneader is common. It is desirable to blend the compatibilizer, colorant and other additives in this step. The selection of the compatibilizing agent and the kneading conditions, and the melt viscosity ratio of the aliphatic polyester containing polyolefin and polylactic acid greatly affect the dispersion average particle size in the film thickness direction of the aliphatic polyester resin containing polylactic acid in the invention. Therefore, appropriate control is necessary.

For the purpose of the invention, by reducing the melt viscosity of the polyolefin resin, it becomes easier for the polyolefin resin to take a sea-island structure, and the blending ratio of the aliphatic polyester resin containing polylactic acid is 40 to 80%. Although it becomes possible, when the melt viscosity ratio is increased, the aliphatic polyester resin containing polylactic acid that becomes an island at the time of kneading is not sufficiently sheared, and it is difficult to achieve fine dispersion. In addition, the compatibilizer acts appropriately to help fine dispersion and to prevent reaggregation of the aliphatic polyester resin containing polylactic acid that is an island after kneading.
Further, when the shear rate at the time of kneading is increased, fine dispersion is progressed, but problems such as heat generation and molecular cutting may occur, so adjustment is necessary as appropriate.

  In order to extrude the compound as a film, it is preferable to use extrusion molding using a T-die, but calendar molding, inflation molding, or the like may be used. Flatness, heat shrinkage, foreign matter management, etc. for ensuring the printability of the post-process may be used. However, it is important that the thickness of the film is in the range of 50 μm to 100 μm.

  The film for decorative sheets of the present invention contains 20-50% by mass of a polyolefin resin having an initial flexural modulus in the range of 700 MPa to 2000 MPa, and an aliphatic polyester resin containing at least polylactic acid in a proportion of 40-80% by mass, By being a film having a thickness in the range of 50 to 100 μm, the aliphatic polyester can at least contain polylactic acid synthesized from plant-derived raw materials, so that the colored film for decorative sheets can be made into a biomass, and the environmental load Can be reduced.

  The colored film for a decorative sheet of the present invention has a sea-island structure in which the aliphatic polyester resin containing at least the polylactic acid is dispersed as islands in the sea of the polyolefin resin, and the polyolefin resin is the cosmetic By being exposed to an area of 70% or more of the total surface area of the colored film for sheets, the resin layer in the film has a sea-island structure with the polyolefin as the sea, thereby reducing heat resistance, which is a weak point of polylactic acid. In addition, defects such as being easily hydrolyzed, weak impact strength, and poor adhesion can be greatly improved.

  Moreover, the colored film for decorative sheets of the present invention has a film forming property and tear strength of the colored film for decorative sheets, because the dispersion average particle size in the film thickness direction of the aliphatic polyester containing at least polylactic acid is 20 μm or less. Printability is greatly improved.

Examples of the present invention and comparative examples are shown below.
The materials and equipment used are shown below. The blending ratio is expressed in mass%, where the total amount is 100.

<Materials used>
Polylactic acid resin (Terramac TP4000 manufactured by Unitika Ltd.).
Polypropylene 1 (Prime Polymer Co., Ltd. Prime Polypro E2000GV, initial flexural modulus: 1600 MPa).
Polypropylene 2 (Prime Polymer Co., Ltd. Prime Polypro E200GV, initial flexural modulus: 1600 MPa).
Polypropylene 3 (Prime Polymer Co., Ltd. Prime Polypro J136, initial flexural modulus: 2100 MPa).
Polypropylene 4 (F5900 manufactured by Prime Polymer Co., Ltd., initial flexural modulus: 500 MPa).
Acid-modified polypropylene (Yumex 1001 manufactured by Sanyo Chemical Industries, Ltd.).
Titanium oxide masterbatch (PEX 6800 White manufactured by Tokyo Ink Co., Ltd.).

<Device used>
Same-direction twin-screw extruder (TEX65 manufactured by Nippon Steel Works).
Single screw extruder (FS-65 L / D = 36 manufactured by Ikegai Iron Works).
Mold 900m width Coat hanger die.

<Device conditions>
[Same direction twin screw extruder condition 1] Extrusion temperature: 210 ° C. setting, screw rotation speed: 250 rpm, extrusion rate: 80 kg / h.
[Same Direction Twin Screw Extruder Condition 2] Extrusion temperature: 210 ° C. setting, screw rotation speed: 100 rpm, extrusion rate: 80 kg / h.
Single screw extruder conditions 230 ° C setting.
Mold temperature 230 ° C setting.

(1) Preparation of Compound 1 Polylactic acid resin: 50% by mass, acid-modified polypropylene (compatibilizer): 10% by mass, polypropylene 1 (polyolefin resin): 30% by mass, titanium oxide master batch (pigment): 10% by mass Were kneaded in the same direction twin screw extruder condition 1 to produce a compound 1.
(2) Preparation of Compound 2 Polylactic acid resin: 50% by mass, acid-modified polypropylene (compatibilizer): 10% by mass, polypropylene 2 (polyolefin resin): 30% by mass, titanium oxide master batch (pigment): 10% by mass Was kneaded under the same-direction twin screw extruder condition 2 to prepare compound 2.
(3) Production of Compound 3 Polylactic acid resin: 50% by mass, polypropylene 1 (polyolefin resin): 40% by mass, titanium oxide masterbatch (pigment): 10% by mass under the same direction twin screw extruder condition 2 Compound 3 was prepared.
(4) Preparation of compound 4 Polylactic acid resin: 50% by mass, acid-modified polypropylene (compatibility agent): 10% by mass, polypropylene 3 (polyolefin resin): 30% by mass, titanium oxide master batch (pigment): 10% by mass Was kneaded in the same direction twin screw extruder condition 1 to produce a compound 4.
(5) Preparation of Compound 5 Polylactic acid resin: 50% by mass, acid-modified polypropylene (compatibilizer): 10% by mass, polypropylene 4 (polyolefin resin): 30% by mass, titanium oxide master batch (pigment): 10% by mass Were kneaded under the same direction twin screw extruder condition 1 to prepare compound 5.

<Example>
Compound 1 was formed into a film having a thickness of 80 μm by a single screw extruder to produce a film for decorative sheet of Example.
<Comparative Example 1>
Compound 2 was formed into a film having a thickness of 80 μm by a single screw extruder, and a decorative sheet film of Comparative Example 1 was produced.
<Comparative Example 2>
Compound 3 was formed into a film having a thickness of 80 μm by a single screw extruder to produce a decorative sheet film of Comparative Example 2.
<Comparative Example 3>
Compound 4 was formed into a film having a thickness of 80 μm by a single screw extruder to produce a decorative sheet film of Comparative Example 3.
<Comparative example 4>
Compound 5 was formed into a film having a thickness of 80 μm by a single screw extruder, and a decorative sheet film of Comparative Example 4 was produced.
<Comparative Example 5>
Compound 1 was formed into a film having a thickness of 30 μm by a single screw extruder to produce a decorative sheet film of Comparative Example 5.
<Comparative Example 6>
Compound 1 was formed into a film having a thickness of 120 μm by a single screw extruder, and a decorative sheet film of Comparative Example 6 was produced.

About the film for decorative sheets of an Example and Comparative Examples 1-6, the exposed area ratio of polyolefin resin and the dispersion average particle diameter of aliphatic polyester resin were measured. The results are shown in Table 1.
Also, film properties were observed, printability, heat and humidity resistance test, and lapping test were performed. The results are shown in Table 2.

The film shape was evaluated based on the presence or absence of occurrence of flare deformation and surface smoothness. The case where there was no flare deformation and the surface of the film was smooth at first glance was indicated as “◯”, the case where it was not so was indicated as “X”, and the case where either one of flare deformation or smoothness was poor was indicated as “Δ”.
Moreover, gravure printing was performed on the decorative sheet film to evaluate the registration accuracy. Observe 10 alignment marks on both sides of the printed film, and mark “O” when the positional deviations are all 0.5 mm or less, and “0.5” to 1 mm. The case where there was even one that was displaced by 1 mm or more was designated as “X”.
Furthermore, the heat and humidity test evaluated the elongation rate of the film before and after leaving the film for decorative sheets in an atmosphere of 60 ° C. and 90% RH for 200 hours. The case where the elongation rate was 20% or less was “◯”, and the case where the elongation was more than 20% was “x”.
Furthermore, the lapping test was evaluated by whether or not whitening occurred at the bent portion of the decorative sheet film when the decorative sheet film was bonded to the curved surface portion having a curvature radius of 1 mm. The case where whitening did not occur was designated as “◯”, and the case where whitening occurred was designated as “x”.

As shown in Table 1 and Table 2, in the examples, the exposed area ratio was 70% or more, and the dispersion average particle diameter was 20 μm or less. The film properties, printability, heat and humidity test, and lapping test were also good.
On the other hand, in Comparative Examples 1 and 2, the extrusion conditions at the time of forming the compound were not preferable, the dispersibility was poor, and the heat and humidity resistance was lowered.
In Comparative Example 3, since the initial flexural modulus of the polyolefin resin was too high, the film properties were slightly deteriorated and the printability was also deteriorated. The film itself was difficult to extrude because of the crystallization of polyolefin.
In Comparative Example 4, the initial flexural modulus of the polyolefin resin was too low, which made printing difficult.
In Comparative Example 5, since the film thickness was too thin, the film was stretched and printing was difficult.
Moreover, in Comparative Example 6, since the film thickness was too thick, whitening occurred in the lapping test.

Claims (5)

  Polyolefin resin having an initial flexural modulus in the range of 700 MPa to 2000 MPa is contained in a proportion of 20 to 50% by mass, and an aliphatic polyester resin containing at least polylactic acid is contained in a proportion of 40 to 80% by mass, and the thickness is in the range of 50 to 100 μm. A film for a decorative sheet, characterized in that it is a film.   The polyolefin resin has a sea-island structure in which the aliphatic polyester resin containing at least the polylactic acid is dispersed as islands in the sea of the polyolefin resin, and the polyolefin resin is 70% or more of the total surface area of the decorative sheet film. The film for decorative sheets according to claim 1, wherein the film is exposed to an area.   The film for decorative sheets according to claim 1 or 2, wherein the aliphatic polyester resin containing at least the polylactic acid has a dispersion average particle size in the film thickness direction of 20 µm or less.   The film for a decorative sheet according to any one of claims 1 to 3, wherein the film contains a pigment and is colored.   The film for decorative sheets according to any one of claims 1 to 4, wherein a compatibilizing agent is contained.