JPH02281063A - Curable silicone composition and mold release agent - Google Patents

Abstract

PURPOSE:To obtain a curable silicone composition consisting of a copolymer containing vinylidene fluoride and/or tetrafluoroethylene and polyfluoralkylvinyl- based copolymer and suitable as a mold release agent for silicone-based tacky agent. CONSTITUTION:The composition containing (A) a copolymer consisting of A1: vinylidene fluoride and/or tetrafluoroethylene, A2: other fluorine-containing monomer (preferably hexafluoropropene) having ethylenic unsaturated bond and containing the component A1 preferably at an amount of 15 to 85wt.% and (B) a copolymer obtained by copolymerizing B1: polyfluoroalkylvinyl monomer (preferably >=4C alkyl) and B2: silicone-based vinyl monomer (e.g. the formula) having one or more groups capable of hydrolyzing Si bond, preferably at a weight ratio of 50/50 to 98/2, preferably in the range of 5 to 2000 pts.wt. component B based on 100 pts.wt. component A.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention particularly relates to a curable silicone composition useful as a mold release agent for silicone adhesives and a mold release agent for silicone adhesives.

[Conventional technology]

Silicone adhesive has excellent heat and cold resistance.

Because it has chemical resistance and electrical insulation properties, it is used in a wide range of applications.

Conventionally, the release agent for release paper used to protect the adhesive surface of silicone adhesives is mainly composed of a copolymer of polyfluoroalkyl vinyl monomers and silicone vinyl monomers containing hydrolyzable groups. A method of curing the copolymer to form a release layer has been proposed (Japanese Patent Laid-Open No. 61-228078).

[Problem to be solved by the invention]

However, although the release layer obtained by the above method has practical release properties against silicone adhesives,
Since the viscosity of the copolymer is low before curing, it has insufficient wettability to substrates such as paper, laminated paper, and films, and repellency is likely to occur when coated. As a result, a good mold release layer is not formed in the repellent areas, resulting in poor mold release properties.

This can cause various troubles. In addition, in substrates with insufficient sealing, such as glassine paper, intense penetration occurs, and as a result, it becomes difficult to obtain a release paper with stable release properties. Particularly, when the mold release agent is diluted with a solvent and used, the above-mentioned repelling and seepage become noticeable, which poses a big practical problem.

The present invention was made in view of the above circumstances, and it is possible to form a cured product that has good wettability to the base material, good releasability, and good residual adhesion of the adhesive, and The object of the present invention is to provide a curable silicone composition suitable as a release agent for adhesives, and a release agent for silicone adhesives made of the composition.

[Means and effects for solving the problem] As a result of intensive studies to achieve the above object, the present inventor found that (a) vinylidene fluoride and/or tetrafluoroethylene and other compounds having an ethylenically unsaturated bond; A copolymer obtained by copolymerizing at least one fluorine-containing monomer, and (b) a hydrolyzable polyfluoroalkyl vinyl monomer bonded to at least one silicon atom in the molecule. When a copolymer obtained by copolymerizing with a silicone-based vinyl monomer containing groups such as Therefore, the function of the cured layer is effectively exhibited, and the cured layer has excellent releasability to the silicone adhesive, and does not impede the adhesiveness of the silicone adhesive after peeling. Therefore, they discovered that it is effective as a release agent for release films for silicone pressure-sensitive adhesives, leading to the present invention. Therefore, the present invention provides a cured silicone containing the above-mentioned components (a) and (b). The present invention provides a composition and a release agent for silicone adhesives comprising the composition.

The present invention will be explained in more detail below.

The copolymer of component (a) used in the composition of the present invention has the effect of suppressing the penetration of the composition of the present invention into the base material, and is a copolymer of vinylidene fluoride and/or tetrafluoroethylene and an ethylenic polymer. It is a copolymer with at least one other fluorine-containing monomer having a saturated bond.

In this case, other fluorine-containing ethylenically unsaturated monomers include hexafluoropropene, pentafluoropropene, trifluoroethylene, trifluorochloroethylene, vinyl fluoride, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether)
, perfluoro(propyl vinyl ether), 2-iodoperfluoropropane, promotrifluoroethylene, and the like.

In the above component (a), particularly preferred copolymers from the viewpoint of raw material availability and cost are vinylidene fluoride-hexafluoropropene binary copolymer and tetrafluoroethylene-hexafluoropropene binary copolymer. ,
It is a vinylidene fluoride-tetrafluoroethylene-hexafluoropropene ternary copolymer.

In addition, in the copolymer of component (a), vinylidene fluoride and/or tetrafluoroethylene component is 1
It is preferably 5 to 85% by weight.

Furthermore, in the composition of the present invention, the copolymer of component (a) does not need to be particularly vulcanized. Therefore, vulcanizing agents such as organic peroxides, polyamines, and polyols, and acid acceptors such as metal oxides and metal hydroxides.

Ingredients are not required.

In addition, the copolymer of the (oral) component used in the composition of the present invention is a polyfluoroalkyl vinyl monomer and a silicone containing a hydrolyzable group bonded to at least one silicon atom in the molecule. It is obtained by copolymerizing with vinyl monomers.

Here, the polyfluoroalkyl vinyl monomer is a vinyl monomer having a polyfluoroalkyl group, and the - portion or Any group that is entirely substituted with fluorine atoms may be used, and vinyl monomers containing such groups include CH,=CHC00CH,CF.

CH2=C(CH,)COOCH,CF,.

CH,=CHC00CH,CF,CF,H.

CH2=C(CH,)COOCR(CF3)2゜CH,
=CHC00CH(CH,)C3F,.

CH,=CHCOOCH,C4F,.

CH2=C(CH,)COOCH,C4F,.

CH2=CHC00CH, (CF, LH.

CH2=　C(CH3)COOC)I,　CGF Engineering,.

CH2=C(CH,)COO(c H2), C, F Eng,.

CH,=CHC00(CH,),C,Ff.

CH,=CH0C,H4C3F Eng.

CH,=CHC00C,H40CH,CF3゜CM,=
CHC00C2H40CH, C4F.

In particular, polyfluoroalkyl groups having a butyl group or higher are preferred from the viewpoint of mold releasability.

The above polyfluoroalkylvinyl monomer is one of the
A single species or a mixture of two or more species may be used.

On the other hand, a silicone-based vinyl monomer containing a hydrolyzable group bonded to at least one silicon atom in its molecule has a vinyl group and silicon for copolymerization with a polyfluoroalkyl group-containing vinyl monomer. and a hydrolyzable group bonded to the atom. Examples of the hydrolyzable group include an acyloxy group or an allyloxy group such as an acetoxy group, an octanoyloxy group, and a benzoyloxy group;
Ketoxime groups such as dimethylketoxime group, methylethylketoxime group and diethylketoxime group; alkoxy groups such as methoxy group, ethoxy group and propoxy group; alkenyloxy groups such as isopropenyloxy group and 1-ethyl-2-methylvinyloxy group; group, dimethylamino group,
Amino groups such as diethylamino group, butylamino group, cyclohexylamino group, aminoxy group such as dimethylaminoxy group, diethylaminoxy group, amide group such as N-methylacetamide group, N-ethylacetamide group, N-methylbenzamino group, etc. These hydrolyzable groups themselves are detached from the silicon atom and scattered outside the system, so they are electronically stable;
It is preferable to avoid substances with large steric hindrance and substances that produce high boiling point substances after hydrolysis.

Therefore, as this silicone vinyl monomer.

CHz ”CHCOO(CH2)3S i (OCH
3) 3-CH,=CHC00(CH,), Si(○C-
Hl)3.

CH2=C(CHa)COO(CHz)a S l
(OCHz )3-CH,=C(CH,)COO(CH
Il), S i (QC, H,),.

CHz = CHCOO(CHz) a Si CH3
(OC2Hs)! +CHyo=C(CH,)COO(
CH,)3SiC,H,(OCH3),.

CH,=C(CHi)COO(CH,)3S i (C
H,)2(OC2H,).

CH,=C(CH,)Coo(CH,), S i (
CH,)* (OCR,).

CHz=CHCOO(CH2)3Si(OCOH))3
*○ CH,=C(CH,)COO(CH,),SiC,H,
(OCCH,)! ! CH,=C:(CH3)C00(C
HJ3SiCH3(NC-CHl)z.

CH.

C:H2=C:HCOO(CH,)3SiCH,(ON
(CH,)C:2H,l.

CH,=CH5i (OCH,)3゜ CH,=CH8i (QC,H,),.

CH1l=CHS i CH3(OCHs)i −
Mouth CH,=CHS i (○-C-CH,),.

CHz=CH3i (CH3)z(OC:tHs).

CH,=CH5i (CH3), S i CH, (o
CHj) * 1CH, =CH8iC,H, (○CCH,
),.

CHz = CHS iG H3 (ON (CH3)
Those represented by QHs)z or their partial hydrolysates are preferably used.

The weight component ratio of the polyfluoroalkyl vinyl monomer and the silicone vinyl monomer containing a hydrolyzable group in the copolymer of component (b) is preferably 50,150 to 98/2, More preferably 70/30-95
It is 15. If the weight component of the polyfluoroalkyl vinyl monomer is less than 50%, the resulting cured film may not have a sufficient release effect on the silicone adhesive, and the cured film may become brittle; Then.

The resulting composition may have poor curability, and the adhesion of the cured film to the substrate may also deteriorate.

The copolymer of component (b) contains methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 1- Butyl methacrylate, 2
- Methacrylates such as ethylhexyl methacrylate, silicon-containing methacrylates such as γ-tris(trimethylsiloxy)silylpropyl methacrylate, γ-bis(trimethylsiloxy)methylsilylpropyl methacrylate, styrene, vinyltoluene, etc. An appropriate amount of an aromatic vinyl compound may be contained.

The copolymer of component (b) can be obtained by copolymerizing each monomer using a radical reaction initiator by a known method such as solution polymerization. Examples of the radical reaction initiator include azobisisobutyronitrile, di-butyl peroxide, dibenzoyl peroxide, t-butyl perbenzoate, and methyl ethyl ketone peroxide. This reaction is preferably carried out in a fluorinated solvent, an acetate-based solvent, or a ketone-based solvent, but the resulting copolymer may have poor storage stability if used as a solvent-containing copolymer without removing the solvent. It is advantageous.

The amount of component (b) to be blended is preferably 5 to 2,000 parts by weight, more preferably 20 to 500 parts by weight, per 100 parts by weight of component (a). If the amount of component (b) is less than 5 parts by weight, the curing speed will be insufficient and it is not practical, and if it exceeds 2,000 parts by weight, the effect of component (b) will be insufficient, resulting in decreased wettability and May cause increased penetration.

In addition to the essential components (a) and (b), various additives may be added to the composition of the present invention as needed. For example, titanium compounds such as tetrabutoxytitanium, dibutyltin diacetate, dioctyl The curing rate of a composition can be increased by the combined use of a curing catalyst for the condensation reaction, such as a tin compound such as tin diacetate.

Furthermore, it is also possible to add fillers such as silica, talc, clay, diatom, carbon black, etc., reinforcing agents, plasticizers, colorants, lubricants, adhesion improvers, and the like.

Further, the composition may be diluted with an organic solvent in which components (a) and (b) are soluble, such as meta-xylene hexafluoride or methyl ethyl ketone, for the purpose of facilitating film formation by coating or the like.

When forming a cured layer on the surface of a substrate using the composition of the present invention to form a release film for a silicone adhesive, the substrate may be one without sealing treatment, such as glassine paper or high-quality paper. ; Examples include polyethylene laminate paper, polyester film, polypropylene film, polyimide film, polyethylene film, etc., but are not particularly limited.

The composition of the present invention can be applied to the substrate using known techniques such as roll coater, spraying, and dipping. In addition, after applying the composition of the present invention to a base material,
It can be cured using known techniques such as room temperature curing, heat curing, and ultraviolet curing, but in order to cure in a short time, 1
It is preferable to heat at a high temperature of 00 to 200'C for 10 to 60 seconds.

[Effects of the Invention] The curable silicone composition of the present invention is suitable as a mold release agent for silicone adhesives, and this mold release agent has the following advantages over conventional mold release agents.

(1) Since it has good wettability to the base material, the resulting cured film is uniform and smooth, and has good releasability from silicone adhesives.

Furthermore, a silicone pressure-sensitive adhesive using this cured film as a release layer has good residual adhesion.

(2) Even if it is diluted with a solvent and coated on a substrate that easily penetrates without sealing treatment, such as glassine paper, it does not penetrate easily and the resulting cured film has stable mold release properties.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples and comparative examples, but the present invention is not limited to the following examples.

[Example, comparative example]

Curable silicone compositions having the formulations shown in Table 1 were prepared using the components (a) and (b) shown below.

F-1: Vinylidene fluoride-hexafluoropropene copolymer with a weight ratio of 60/40 (intrinsic viscosity measured in methyl ethyl ketone at 35°C is 0.95) F-2: Vinylidene fluoride -Tetrafluoroethylene-hexafluoropropene copolymer with a weight ratio of 40/30/30 (intrinsic viscosity measured in methyl ethyl ketone at 35°C is 0.93) (CH,)COOC,H4C,F,□/CH
,=CH8i(QC,H,)a(7) weight ratio is 90/1
■-2=CH,=CHC00C,H4C,F? /c Hz
Composition ■-3 consisting of 50 parts by weight of a copolymer with a weight ratio of =CH8i(QC,H,) of 90/10 and 52-750 parts by weight of Daiflon: CH, = C(CH,)COOC,H4C, F engineer? /
CH-=C(CH,)COO(CH,)3Si(OC
A composition consisting of 50 parts by weight of a copolymer of R, ) in a weight ratio of 90/10 and 50 parts by weight of Daiflon 52-T.Next, the physical properties of each composition obtained above were evaluated by the following method.

(1) The wettability composition was applied to a polyester film having a thickness of 38 μm using a wire bar &5, and the occurrence of repellency on the applied surface was observed.

(2) The soak-in composition was applied to 50 g/rd glassine paper without sealing treatment using a wire bar Nα18, and the permeation of the treatment liquid to the back surface of the substrate was observed.

(3) Apply the release composition to 50g/rrF glassine paper without sealing treatment using Wire Barma 14, and heat it at 160°C for 60 seconds using a hot air circulation dryer to form a cured film. formed.

This cured film surface was laminated with the adhesive surface of a 38μ thick polyester film coated with a 20μ thick silicone adhesive (Shin-Etsu Chemical Division KR-120), and pressure bonding was performed at 70°C for 20 hours under a load of 20g/aJ. I did it.

Next, using a tensile tester, the peeling angle was 180° and the peeling speed was 0.
．． The adhesive surface was peeled off at a rate of 3 m/min, and the force (g) required for peeling was measured.

(4) Residual adhesive strength On the adhesive surface peeled from the cured film surface using the method (3) above,
Paste an aluminum plate, press it with a 2 kg rubber roll, and after 2 hours, peel off the adhesive side at a peel angle of 180" and a peel speed of 0.
．． The force (g) required for peeling was measured by peeling at 3 m/min.

Table 2 shows the evaluation results for each physical property.

Claims (1)

[Claims] 1. (a) A copolymer obtained by copolymerizing vinylidene fluoride and/or tetrafluoroethylene with at least one other fluorine-containing monomer having an ethylenically unsaturated bond. and (b) a copolymer obtained by copolymerizing a polyfluoroalkyl vinyl monomer and a silicone vinyl monomer containing a hydrolyzable group bonded to at least one silicon atom in the molecule. A curable silicone composition comprising: 2. A mold release agent for a silicone adhesive comprising the curable silicone composition according to claim 1.