JPS60245683A - Release sheet - Google Patents

Abstract

PURPOSE:To provide a release sheet having an excellent barrier property against a release agent soln., release agent adhesion and heat resistance, by providing a release layer on a sheet support through a primer layer composed of a soap-free acrylic resin emulsion and oxidized starch. CONSTITUTION:In a release sheet in which a release layer is provided on at least one side of a sheet support through a primer layer, the primer layer is formed from a soap-free acrylic resin emulsion and oxidized starch. If desired, further a melamine/formaldehyde resin may be added to the primer layer forming component to carry out an intermolecular crosslinking reaction between the acrylic resin and the oxidized starch and an intramolecular crosslinking reaction, whereby adhesion to the substrate and resistance to heat and water can be improved. The oxidized starch is used in a quantity of 3-200pts.wt. (on a solid basis) and the melamine/formaldehyde resin is used in a quantity of 0.3- 30pts.wt. (on a solid basis) per 100pts.wt. (on a solid basis) acrylic resin emulsion.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a release sheet comprising a sheet-like support and a release agent layer provided on at least one side of the support via an undercoat layer.

[Problem that the invention seeks to solve]

Currently, a wide variety of release sheets are used for adhesive products such as adhesive tapes and labels, and for manufacturing processes of synthetic leather, molded products, etc., such as polyvinyl chloride synthetic leather and carbon fiber prepreg. The performance required of the release sheet here is that in the case of a sticky product, it should protect the surface of the adhesive sheet and have good peelability during use, and in the case of a product used in the manufacturing process, it should have good peelability. It has good peelability, has sheet strength suitable for each process, and has good heat resistance. Such a release sheet has a sheet-like support with a release agent layer provided on one side via an undercoat layer.

As the sheet-like support, an inert pot molecule film, a metal foil 2 paper substrate, a nonwoven fabric, etc. may be used. Among these sheet-like supports, it is difficult to obtain desired releasability with a polymeric film having an inactive surface, and its use when used alone is limited. Moreover, for molecular film and metal foil, there is no undercoat that has good adhesion with the release agent. Sex is not obtained.

- Of the sheet-like supports, the paper base material is suitable for use with any release agent if properly removed.
By forming a uniform thin layer on the surface of a paper base material, a release sheet with stable releasability can be obtained and is used in a wide variety of applications. Currently, there are three types of underlayers: (1) those coated with clay pigments, (2) those coated with water-bathable polymers such as polyvinyl alcohol, and (3) those coated with extruded polyethylene. However, ()) has poor adhesion with release agents, (2) has poor heat shrinkage resistance, and (3) has poor heat resistance.

Conventional release sheets, such as those used in the past, have a number of drawbacks, and a wide variety of adhesive products ((required performance and manufacturing process) can meet all of the required performances of release sheets. There is no release sheet with a satisfactory bobbin thread layer, and such a release sheet is desired.

[Object of the Invention] The object of the present invention is to improve the above-mentioned drawbacks and to improve the release agent coating liquid barrier property, release agent adhesion, 1llIt heat resistance and +fi
To provide a heat-shrinkable base material for a release sheet.

[Structure of the invention]

The release sheet according to the present invention is formed on at least one side of a sheet-like support, and the lower thread layer is formed of a glue-free type acrylic resin emulsion (712) (or starch), It is characterized by being formed from formaldehyde resin.

That is, a 2-p-free type acrylic resin emulsion and oxidized starch, or a melamine-formaldehyde resin added to one or both sides of a sheet-like support.
By applying a H4 cloth, drying the tape, and providing a release agent layer, the release note of the present invention can be obtained which has excellent release agent coating solution barrier properties, release agent ZH properties, heat resistance, and heat shrinkage resistance.

Examples of the sheet-like support constituting the release sheet of the present invention include a paper base material, a nonwoven thin molecular film, and metal oil. These materials may be used alone, or may be used in the form of a laminate with alternate layers.

Paper thread A is usually tsubo m: 5fJJ)-30
09/m,', 60 to 650μ thick kraft paper, high quality, single generation paper, white paperboard, etc. are used.

As a non-woven fabric, 7 bends, basis weight 1U ~ 150,497M
, manufactured by a dry method, a wet method, or a direct method and having a thickness of 50 to 400 μm is used.

Examples of polymer films include polyethylene, polypropylene, bolybdenum, polymethylpentene, methylpentene co-y1 (combined) polyolefin film, polyethylene terephthalate film, polysalt 1-hibinyl film, polyjλA (vinylidene), etc., with an IV of 5 to 150μ. Film, fluorine (☆1 fat film, polyhexamethylene)
Get rid of adipamide film, etc.

[Gold] Copper foil, aluminum foil, tin foil, etc. with a thickness of 5 to 100 μm are used as the foil.

The soap-free type acrylic resin emulsion used in the present invention is one that does not contain a surfactant that acts as a milking agent, or contains two or more surfactants per 100 parts by volume of acrylic resin solid content.
Less than 1" part by weight of acrylic resin emulsion.

A good acrylic resin emulsion containing an ifJ activator generally includes ()) one that has been milked with a protective colloid; There is an aqueous dispersion of acrylic resin copolymerized with a polymer-forming monodensate, but according to the inventors' studies, (1) is inferior in release agent density and water resistance, and (2) is inferior in release agent density and water resistance. It is not suitable for use in the present invention because it has poor solvent resistance, which is required when applying a solvent-based release agent.

(3) does not have the disadvantages seen in (]) and (2) and can be used. However, the 1 used in the present invention
It is preferable to use a soap freeter/f-acrylic resin emulsion containing at least 2 parts by weight of a nonionic or anionic surfactant per 100 parts by weight of the solid content of the acrylic resin.
More preferably, it is an acrylic resin emulsion containing a low surfactant of 74% by weight (containing S or more). It can be prepared by polymerizing a thread containing less than 30% of surfactant.

A conventional so-called Two Buoy 7 type acrylic resin emulsion prepared by using a relatively large amount (i.e., about 5 parts by weight or more per 100 parts of fat solids) of milk is a milk (
The adhesion of the release agent and the adhesion of the paint film are poor due to the influence of the arsenic.

The above-mentioned low surfactant-containing acrylic resin emulsion preferably used in the present invention is disclosed in Japanese Patent Application Laid-Open No. 54-886.
It is described in Japanese Patent No. 92.

The acrylic resin emulsions used in the present invention are prepared by known milk polymerization methods, such as those described in the above-referenced patent application. Acrylic acid esters are the monomers that make up acrylic resin.

Consists of a combination of methacrylic acid esters and vinyl monomers copolymerizable with these esters. Examples of acrylic esters include methyl acrylate, ethyl acrylate, n-
Butyl acrylate? -Ethylhexyl acrylate, etc., and the methacrylic acid ester is methyl methacrylate.

Examples of copolymerizable vinyl monomers include ethyl methacrylate, n-butyl methacrylate, and glycidyl methacrylate. Examples of copolymerizable vinyl monomers include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and itaconic acid, acrylamide, and methacrylamide. .

Examples include acrylonitrile and styrene. A preferred combination of monomers is an acrylic acid ester-based component combined with a small amount of an unsaturated carboxylic acid and acrylonitrile.

The acid used in the present invention (arsenic starch is usually used as a coating/binder, and the stability is improved by modifying the starch with an acid such as sodium hypochlorite [arsenic agent]. It has a low degree of polymerization through hydrolysis with an agent, and has good fluidity in a solution state.

In addition, the melamine-formaldehyde resin used in the present invention is a product obtained by adding formaldehyde to melamine. Improves adhesion, heat resistance and water resistance.

In the present invention, the role of the soap-free type acrylic resin emulsion is to provide film-forming properties, to form a close layer with the sheet-like support and the release agent, and to improve the bath agent property of the surface of the film and the heat applied during each processing step. Due to the history, the base material is heat shrinkable (
= I slope. Also, acid r acetate starch is a febrile beggar]
-The melamine/formaldehyde resin exhibits heat regeneration properties for soap-free acrylic resin, and the adhesion to the base material and water resistance for acid starch. .

The formulation that can be used in the present invention is oxidized starch to 20 parts by weight (solid content), preferably 5 to 5 parts by weight (solid content) of soap-free type acrylic resin emulsion.
0 parts by weight (solid content). Further, the melamine formaldehyde resin is 0 parts by weight (solid content), preferably 1 to 15 parts by weight (solid content).

The purpose of the present invention is to improve the processability and other properties of a soap-free type acrylic resin emulsion and oxidized starch, or of these and melamine/formaldehyde resin into a sheet-like support, as long as the purpose of the present invention is not impaired. It is optional to add viscosity modifiers, wetting agents, film forming aids, etc.

When forming a bottom layer on a sheet-like support using a soap-free acrylic resin emulsion and oxidized starch, or using these and melamine/formaldehyde resin, apply the coating liquid using a roll coater, etc. according to a conventional method. All you have to do is coat it with mineral cloth, dry it, and harden it.

The release agent used is not particularly limited (any known release agent can be used, such as silicone resins and non-silicone resins such as long button alkyl acrylate polymer resins, and Formation can also be carried out according to conventional methods.

The release agent according to the present invention has a barrier property against release agents,
Release agent adhesion, surface J heat resistance, and heat-resistant elasticity are vague. This is reflected in the following examples, although the present invention is in no way limited thereto.

Example 1-4 As a sheet-like support, (11 high quality paper (basis weight 649/m
.

(thickness 80μ), +2 Rouyon 2 based non-containing cloth (basis weight dog/m, thickness 116μ), +31 polypropylene 7 film (thickness 50zl), (41A, g foil (thickness 50μ) 7 used, A soap-free type acrylic resin emulsion (trade name [Bonlon S-482
J: 100 parts by weight of Mitsui Toatsu [manufactured by Higakusha Co., Ltd.] and oxidized starch (product name ``Ace A'': manufactured by Egg Corn Starch Co., Ltd.) 5
A 25% by weight aqueous dispersion with 0 parts by weight (all based on solid content) was coated with a roll coater at 5 g/m'' (solid content) and dried. To (
1) Soap-free type acrylic resin emulsion (i
Product name: Bonron S-482J: Mitsui Toatsu 1 Higakusha),
+21 acid [Ace starch (product name “Ace A”: egg corn/
(manufactured by Starch), U pigment coating liquid (clay/S'B R latex weight ratio = IDO/20, concentration 48% by weight), t
41 polyvinyl alcohol (PVA) and +51 polyethylene (PE) were coated, respectively, and comparative samples (1 to
20) I made this request.

For each sample, release agent coating liquid barrier properties.

The results of measuring release agent adhesion, heat resistance and heat shrinkage resistance are shown in Table 1.

Example 5-8 As a sheet-like support, (5) high-quality paper (basis weight 6'1 g/
m.

80μ thick), (6) Rayon-based non-woven fabric (
Basis weight (19/m', thickness a 115μ), (71 polypropylene film (1!Q 50μ), (s) Ae foil (thickness 50μ) were used, and the support was soap-free type. Acrylic resin emulsion (product name: Bonron S
-482J: manufactured by Mitsui Toatsu 1ji Gakusha) 100 parts by weight ratio 5s (ih product name r Ace A'': manufactured by Tamako Corn Scooch Company) 60% military health and / melamine formaldehyde resin (product name [Neelamin Bee 65004: Mitsui Toatsu [manufactured by Higakusha] Aqueous dispersion of 25 parts by weight (all based on solid content)? Roll co? - was coated at 5 yen/m' (solid content) and dried. In addition, due to diplomatic ties between the Philippines and China, ``2 Supports 1'' (1) Nobu-free Taifu.

Acrylic tree one-finger emulsion (product name: “Bonron S-4”
82J:Eff1EfHigakusha), (2)(gi(
Starch starch (Product name 1 Ace A: Oji Corn Starch Company V
>, (31 pigment coating liquid (clay/s no 3R latex weight ratio -100/20, a[48% by weight), (4
1 polyvinyl alcohol (PVA), polyethylene (PE) and comparative samples (21~
40) I made this request.

For each sample, resistance to release agent coating liquid and clearing agent.

The results of measuring release agent adhesion, heat resistance and heat shrinkage resistance are shown in Table 2.

In addition, the 11 laws of each Shinkaishi are as follows.

(1) Against peeling 1 (agent coating liquid) Silicone peeling agent coating liquid diluted with toluene (barrier property)
11:5% by weight) and visually inspected to see how the coating liquid had penetrated.

(2) Release agent adhesion A sample coated with AiJ (1) was dried and hardened.

Next, toluene was applied to this coated surface and visually observed to see if the silicone remover had fallen off.

(3) Place the heat-resistant sample in a hot lice dryer at 150'C for 1 minute,
The state of rupture of the primer coating was visually observed.

(4) Heat Shrinkage Resistance (Heat Shrinkability) After heating the sample to 150°C, measure the shrinkage rate that occurs when cooling the sample to 20°C.

〔Effect of the invention〕

By combining a soap-free type acrylic resin emulsion with an acid (arsenic starch), or by further containing melamine/formaldehyde resin as necessary, we can improve the barrier properties of coating fluids with release agents, adhesion of release agents, mt
A release sheet satisfying both heat resistance and heat shrinkage resistance was obtained. Therefore, the releaseable IL sheet of the present invention is extremely useful in adhesive products such as adhesive tapes and labels, and in process release paper used in the manufacturing process of polysalt [hibinyl synthetic leather, carbon fiber prepreg, etc.].

(1 other person)

Claims (1)

[Claims] (117 A release sheet comprising a release agent layer provided on at least one side of a sheet-shaped support via an undercoat layer, wherein the undercoat layer is formed from a nope-free type acrylic resin emulsion and oxidized starch. (2) The release sheet according to claim 1, wherein the undercoat layer forming material further contains a melamine formaldehyde resin.