JPH0753750A - Mold release film - Google Patents

Abstract

PURPOSE:To prepare a mold release film useful for molding of a matted sheet consisting of a resin such as vinyl chloride resin, polyurethane or acrylic resin. CONSTITUTION:A mold release film for resin molding is prepared by forming a coating film which contains a partly hydrolyzed polysiloxane having a hydroxyl group in the side chain or at the terminal, on at least one side of a polyester film having a surface roughness (Ra) of 0.05mum or above and a glossiness of 80% or less directly or through a primer layer consisting of a water-soluble organic silane compd. interposed between them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film for resin molding, and more particularly to a release film useful for molding a matte sheet made of a resin such as vinyl chloride resin, polyurethane or acrylic resin.

[0002]

2. Description of the Related Art In recent years, in the molding of plastics, rubbers, etc., particularly in the molding of sheets of vinyl chloride resin, epoxy resin, polyurethane, polyester resin, etc., in order to maintain its moldability, solidification or curing reaction is usually performed. Process
The resin is cast on a film or paper coated with silicone or the like.

Among these resins, for example, in vinyl chloride resin molding, a sheet is often a soft sheet or leather, and its surface is matte with an uneven pattern resembling leather or fabric. There are many.

As a method for matting the surface of a vinyl chloride sheet with unevenness, usually, embossing is performed in the step after the sheet is formed, for example, it comprises an embossing roll having a desired unevenness pattern and a backup roll, and further at about 150 ° C. There is a method of embossing using an embossing device having a heating device.

However, with such a method, in order to deal with various vinyl chloride sheets, capital investment for the embossing device and cost increase cannot be avoided. Further, it is technically time-consuming to form a matte surface due to minute irregularities on the sheet surface.

[0006]

DISCLOSURE OF THE INVENTION The present inventor has noticed that the above problems can be solved if an uneven pattern can be formed on the sheet surface during sheet forming, and a release film capable of forming a fine uneven pattern on the sheet surface is provided. As a result of earnest research for development, the present invention has been achieved.

[0007]

Means for Solving the Problems That is, the present invention provides a polysiloxane having a surface roughness Ra of 0.05 μm or more and a glossiness of 80% or less on at least one side thereof and having a hydroxyl group at a side chain or a terminal. A release film for resin molding, comprising a coating film using a partially hydrolyzed product.

The polyester in the present invention is a linear saturated polyester produced from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative, and specifically, polyethylene terephthalate, polypropylene terephthalate, Examples include polybutylene terephthalate and polyethylene-2,6-naphthalate. Further, it may be a copolymer in which a part of them is substituted with a third component, or a mixture with a polyalkylene glycol or another resin.

The polyester film of the present invention is
Basically, it can be manufactured by a conventionally known method. For example, the polyester is dried and then melted,
It is extruded from a die (for example, T-die, I-die, etc.) onto a cooling drum and rapidly cooled to obtain an unstretched film, which is then stretched 2 to 4 times in the machine direction and 2 to 4 in the transverse direction. Four
It can be manufactured by double stretching and heat setting at 180 to 240 ° C. The film thickness is not particularly limited, but is preferably 5 to 200 μm.

Surface roughness R for polyester film
It is not necessary to be transparent from the viewpoint of a and glossiness, and from the viewpoint of the slipperiness and processability of the film, a lubricant such as inorganic fine particles such as calcium carbonate, kaolin, silica, titanium oxide and / or catalyst residue It may be a film containing precipitated fine particles or the like, or may be a film containing other additives such as an antioxidant such as sodium dodecylsulfonate and a color tone adjusting agent.

In order to impart a surface roughness (Ra) of 0.05 μm or more and a glossiness of 80% or less to a polyester film, a lubricant having a large particle size, for example, silicon oxide, titanium oxide, calcium carbonate, glass beads, silicone is used. It is preferable to contain resin particles, cross-linked polystyrene particles and the like, for example, it is preferable to add 0.1 to 5.0% by weight of silicon dioxide having an average particle diameter of 1 to 10 μm based on the weight of polyester. The surface roughness Ra of the film is 0.1.
It is preferably at least μm, more preferably at least 0.2 μm.

In the present invention, the water-soluble organic silane compound used for forming the undercoat layer has a structure having a hydrolyzable group usually bonded to a silicon atom and various organic functional groups. is there. This undercoat layer is preferably present from the viewpoint of long-term stability of the release layer.

Examples of such water-soluble organic silane compounds include γ-aminopropyltrimethoxysilane and γ
-Aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane , Γ
-Glycidoxymethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (aminopropyl) -γ-aminopropylmethyl Dimethoxysilane, N-β- (aminoethyl)-
γ-aminopropyltriethoxysilane and the like can be mentioned. These are examples of a part of the water-soluble organic silane compound that can be used in the present invention, and the present invention is not limited thereto. In addition, the water-soluble organosilane compound is 1
One kind or two or more kinds can be used.

The hydrolyzable group in the water-soluble organic silane compound is considered to form a hydroxyl group by hydrolysis and strengthen the bond with the hydroxyl group of the polysiloxane partial hydrolyzate coated on the undercoat layer. In addition, the highly active organic functional group has a strong affinity with the polyester film and the binder resin for the coating layer. For example, the primary or secondary amino group in the molecule has many functional groups such as a hydroxyl group, a carboxyl group and an epoxy group. It is believed that the bond between the film and the undercoat layer and the bond between the undercoat layer and the overcoat layer are strengthened.

The water-soluble organic silane compound is usually used as an aqueous solution at a concentration of 0.1 to 5.0%, and the coating amount on the surface of the polyester film is 0.02 to 0.
2 g / m ² (after drying) is preferred. The application of the water-soluble organic silane compound may be carried out during the polyester film forming process, or may be carried out at a place different from the film forming process.
When it is carried out in the film forming step, it can be applied to an unstretched film, a uniaxially stretched film (particularly a longitudinally stretched film), a biaxially stretched film, a biaxially stretched film and a film after heat setting. Of these, it is preferable to apply the composition to a longitudinally stretched film before it is subjected to transverse stretching. Examples of the coating method include spin coating, gravure roll coating, kiss coating, bar coating,
Various coating methods such as a reverse roll coating method can be used. The coating is on one or both sides of the polyester film.

In the present invention, the polysiloxane partial hydrolyzate having a hydroxyl group at the side chain or terminal forming the release layer is a tetrafunctional silicon compound such as (Cl ₂ Si).
O) n or other chloropolysiloxane, or an alkoxysilane that easily hydrolyzes, or an alkoxypolysiloxane such as ethyl silicate that is partially hydrolyzed by the action of water. A compound represented by the following formula in which 80% or more is substituted with a hydroxyl group (however, for convenience, it is shown that all of the side chains are substituted with a hydroxyl group).

[0017]

[Chemical 1]

Since this partial hydrolyzate dissolves in alcohol, it is used as an alcohol solution, and applied directly on the polyester film or on the undercoat layer and dried by heating to form a film. In this heating and drying, the silanol which is hydrolyzed by the water in the atmosphere causes a condensation reaction to form a three-dimensionally bonded silicon oxide film.

These reactions are known, and are schematically shown as follows.

[0020]

[Chemical 2]

This partial hydrolyzate can be obtained from the market, and examples thereof include Colcoat P, Colcoat R, Colcoat 920 and the like.

The release layer is directly on the polyester film,
Alternatively, when provided on an undercoat layer using a water-soluble organosilane compound, as a coating method, a conventionally known method such as a doctor blade method, a bar coating method, a gravure roll coating method, a reverse roll coating method or the like is used. it can.

The release film of the present invention is a release film for molding a matte sheet made of a resin such as a vinyl chloride resin or a polyurethane resin, and exhibits a stable release property with stable coating adhesion for a long period of time.

[0024]

EXAMPLES The present invention will be further described below with reference to examples. The film characteristics in the examples were measured by the following methods.

(1) Surface roughness Ra of film Using a stylus type surface roughness meter (Surfcoder 30C) manufactured by Kosaka Laboratory Ltd., a chart (under a condition of a needle radius of 2 μm and a stylus pressure of 30 mg ( Cover the film surface roughness curve).
From the film surface roughness curve, extract the part of the measurement length L in the direction of the center line, and draw the center line of this extracted part as X
Axis, the vertical magnification direction is the Y axis, and the roughness curve is Y = f
When represented by (x), R given by the following equation (Equation 1)
a (μm) is defined as the film surface roughness.

[0026]

[Equation 1]

(2) Gloss of film Digital gloss meter GM-3D (Murakami Color Research Laboratory Co., Ltd.)
Manufactured by K.K., and the glossiness at a measurement angle (specular reflection angle) of 60 ° is measured.

[0028]

Example 1 Molten polyethylene terephthalate containing 1.5% of silicon dioxide having an average particle size of about 6 μm added to a polyester was extruded from a die and adhered while applying electrostatic force on a rotating cooling drum maintained at about 40 ° C. It is rapidly cooled to obtain an unstretched film, and the unstretched film is stretched 2.8 times in the machine direction and then 3.0 times in the cross direction, and then 2 times.
Heat setting was performed at 20 ° C. to obtain a biaxially stretched polyethylene terephthalate film having a thickness of 75 μm. This film had a surface roughness Ra of 0.38 μm and a glossiness of 40%.

A partial hydrolyzate of tetraalkoxysilane, Colcoat P, manufactured by Colcoat Co., Ltd., was diluted with isopropyl alcohol (IPA) to prepare a solution having a solid content of 1.5%.

The coating solution was coated on the biaxially stretched polyethylene terephthalate film at a coating amount of 6 g / m ² (wet) and dried at a drying temperature of 120 ° C. for a drying time of 1 minute.

A sheet-shaped vinyl chloride resin was obtained by casting a vinyl chloride resin on the release film thus obtained and then releasing it. Also,
The surface of the released resin sheet was a matte surface.

[0032]

[Comparative Example 1] Molten polyethylene terephthalate to which silicon dioxide having an average particle size of about 0.6 μm was added at 0.2% based on the weight of polyester was extruded from a die and electrostatically applied on a rotating cooling drum maintained at about 40 ° C. Adhesion and quenching were performed to obtain an unstretched film, which was then stretched 3.6 times in the machine direction and then 3.9 times in the transverse direction, and then heat set at 220 ° C. to a thickness of 75 μm. To obtain a biaxially stretched polyethylene terephthalate film. The film had a surface roughness Ra of 0.02 μm and a glossiness of 92%.

A partial hydrolyzate of tetraalkoxysilane, Colcoat P under the trade name of Colcoat Co., Ltd. was diluted with isopropyl alcohol (IPA) to prepare a solution having a solid content of 1.5%.

The coating solution was coated on the biaxially stretched polyethylene terephthalate film at a coating amount of 6 g / m ² (wet) and dried at a drying temperature of 120 ° C. for a drying time of 1 minute.

A vinyl chloride resin in a sheet form was obtained by casting a vinyl chloride resin on the release film thus obtained and then releasing it. The surface was glossy.

[0036]

Industrial Applicability According to the present invention, it is possible to provide a release film which has excellent releasability with respect to a resin such as vinyl chloride resin and which forms a matte on the surface of the released resin sheet. it can.

Claims (2)

[Claims] 1. A coating film using a partial hydrolyzate of polysiloxane having a side chain or a terminal hydroxyl group on at least one side of a polyester film having a surface roughness Ra of 0.05 μm or more and a glossiness of 80% or less. A release film for resin molding, characterized by being provided. 2. A polyester film having a surface roughness Ra of 0.05 μm or more and a glossiness of 80% or less is provided with a hydroxyl group on a side chain or a terminal via an undercoat layer containing a water-soluble organosilane compound. A release film for resin molding, comprising a coating film using the partially hydrolyzed polysiloxane.