JPS61174284A - Silicone composition for use as releasing agent - Google Patents

Abstract

PURPOSE:To provide a silicone composition for use as a releasing agent which exhibits a low peel rate and light peeling and only a slight increase in peel force even in the case of a remarkable increase in peel rate, by mixing a specific two kinds of organopolysiloxanes with an organohydrogenpolysiloxane and platinum. CONSTITUTION:A silicone composition for use as a releasing agent is prepared by mixing (A) 100pts.wt. of an organopolysiloxane of the formula I (wherein R<1> is a monovalent unsaturated hydrocarbon; R<2> is a monovalent hydrocarbon; sand a+b<=3) with (B) 0.1-10pts.wt. of an organohydrogenpolysiloxane of the formula II (wherein R<3> is a monovalent hydrocarbon; and c+d<=3), (C) 0.1-10pts.wt. of an organopolysiloxane of the formula III (R<4> is a monovalent hydrocarbon; R<5> is a polyoxyalkylene; e and n are 0-5; f is 0-200; g is 1-10; h is 1-20; i is 1-50; j is 0-50; and m is 1-4) containing a polyoxyalkylene group in an amount of 3-50wt% per molecule and (D) 0.001-1pt.wt. of platinum (or its compound).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to silicone compositions for mold release, particularly those that are easy to release at low speeds and tend to have an increased release force even when the release speed is increased [771]. This invention relates to a mold release silicone composition with a small size.

(Prior art) Paper - In order to prevent adhesion or sticking between a base material such as processed paper or plastic film and an adhesive substance, pressure is applied to form a silicone film on the surface of the base material to impart mold releasability. It is well known that the releasability of this silicone film varies greatly depending on the type of base material and the type of adhesive substance that is bonded to the silicone film. The force required for peeling (hereinafter referred to as peeling force) varies greatly depending on the peeling speed (hereinafter referred to as peeling speed), and generally the peeling force increases as the peeling speed increases.

And, one peeling speed is 01 to 1'O to increase this peeling force.
Regarding silicone compositions for one-release molds, the lower the peeling force at a low speed such as 1 min, the greater the strength when the peeling speed is set at a high speed such as 30 to 300 m/min. Although it is desirable to keep the peeling force as small as possible when the peeling speed is low or high, at present, the peeling force is small at low peeling speeds, but the peeling force is large at high peeling speeds. It is said that the peeling force is increased at a peeling speed and the peeling force is decreased at a high peeling speed.

(Structure of the Invention) The present invention relates to a silicone composition for mold release that solves the disadvantages of Tx and has a low peeling force at low peeling speeds and a relatively small peeling force at high peeling speeds. b) General formula % formula % or substituted monovalent hydrocarbon group, a-b is a positive number, a+b≦3
) (where R is the same or different unsubstituted or substituted monovalent hydrocarbon group -c-d
is a positive number and c + d≦3) 0.1 to 10 parts by weight of organohydrodiene polysiloxane; The hydrocarbon group -R5 is a polyoxyalkylene group represented by the formula % (R is the hydrogen atom size 1
(valent organic group) -e is θ~5- f is O~50 - n is O
0.1 to 10 parts by weight of an organopolysiloxane containing 3 to 50% by weight of a polyoxyalkylene group represented by 5-5-m is a positive number of 1 to 4 in one molecule - platinum or platinum compound 0. 001 to 1.0 parts by weight.

To explain this, the present inventors have developed a silicone for mold release in which the peeling force does not increase particularly even when the peeling speed is high.
As a result of various studies on obtaining a mold release silicone composition, we have developed a so-called addition reaction type organosiloxane composition consisting of a vinyl group-containing siloxane, an organohydrodiene polysiloxane, and a platinum catalyst, which is known as a silicone composition for mold release. It was discovered that adding an organosiloxane containing (R5in1., ) units and polyoxyalkylene groups in the molecule can reduce the peeling force under high-speed peeling, and the type of organosiloxane added to this - The present invention was completed by conducting research on the amount of addition, etc.

The organopolysiloxane as component (a) constituting the composition of the present invention has a general formula of a vinyl group, an allyl group, an aliphatic monovalent unsaturated hydrocarbon group such as an ethynyl group, and R is a methyl group, an ethyl group, or a furoyl group. - Alkyl groups such as butyl groups - Cycloalkyl groups such as cyclohexyl groups - Phenyl groups - Aryl groups such as biphenyl and naphthyl groups, tolyl groups - xylyl groups - alkaryl groups such as ethylphenyl groups, or carbon atoms of these groups. A chloromethyl group, a fluoromethyl group, and a 3,3.3-trifluoropropyl group in which some or all of the bonded hydrogen atoms are substituted with a halogen atom or a cyano group.

Monochlorophenyl group - the same or different unsubstituted or substituted monovalent hydrocarbon selected from cyanomethyl group, etc.
Both a and b are positive numbers and a + b ≦ 3, but there is no particular restriction on the molecular structure of this one, which is @ chain-branched octopus-like partially cross-linked. It may be either of these or a mixture thereof.

However, it is necessary to contain an aliphatic monounsaturated hydrocarbon group represented by R in the molecule, and this content is 0.
If it is less than 0.05 mol%, the curing rate of the composition will be slow, and if it is more than 31.15 mol%, the mold releasability will be reduced.
Although it is preferable to set the amount to 5.0 mol %, this unsaturated group does not necessarily have to be at the end of the molecular chain.

In addition, although there is no particular limit to the viscosity of this organopolysiloxane, since this composition is usually applied to a substrate as a diluted solution in a solvent, the adhesion to the substrate and the prevention of repelling during coating are important. For this reason, it is desirable that the measured value at 25° C. be 1,000 centipoise or more.

Furthermore, the organohedlodiene polysiloxane as a component constituting the composition of the present invention has the general formula R8Hd.
It is represented by S i○4-(.+.), where R3!2'' is the same monovalent hydrocarbon group as R mentioned above, and -c-d are all positive numbers, and o + d≦3. but.

There are no restrictions on the molecular structure of this product; it is linear, monobranched,
It may be either cyclic or partially cross-linked - or a mixture thereof.

Next, the organopolysiloxane as the c) component constituting this composition is considered to be an essential component to achieve the object of the present invention, and is represented by the general formula %), where R4 is The same monovalent hydrocarbon group as R2 described above, R is a hydrogen atom or a monovalent organic group, and this organic group includes a methyl group, an ethyl group, a probyl group, a butyl group, - lower alkyl groups such as ethylhexyl group, acetyl group - acyl group such as benzoyl group, etc.
e is O~5. f is 0-200-g is 1-10. h is 1~
20,1 is 1~50-j is・0~50-n is 0~5-m
is a positive number from 1 to 4. 2 This organosiloxane has the formula R5in0. li
If the silicone film obtained from this composition does not contain the siloxy group represented by 1], the peelability of the silicone film obtained from this composition will be high under high-speed peeling [1], and the adhesion between the silicone film and the substrate will be poor. The coating becomes easy to fall off from the base material.

Furthermore, if the polyoxyalkylene group present in the molecule is less than 3% by weight, the effect of reducing the peeling force under high-speed peeling of the silicone film obtained from this composition will be insufficient. If this happens, the adhesion between the silicone film and the base material will be poor, and the film will easily fall off from the base material.
It is necessary to contain % of reprints.

In addition, platinum or a platinum compound as the component 2) constituting the composition of the present invention is a known catalyst component for the addition reaction of the component 1), which includes platinum black-alumina. -Solid platinum supported on a carrier such as silica Monochloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of chloroplatinic acid and olefins -Reaction products of chloroplatinic acid and organosiloxanes containing unsaturated groups, etc. Illustrated.

The composition of the present invention can be obtained by mixing predetermined amounts of the above-mentioned components (a) to (2).

These compounding ratios are a) component and 0) component is a) aliphatic unsaturated group bonded to a silicon atom in the component and a) silicon atom (bibonded hydrogen atom) in the molar ratio C 2 and 0
．． When the number is 2 or less or 20 or more, these addition reactions C:
In this case, the silicone component that does not participate in the reaction ζ2 becomes excessive and interferes with the curing reaction.
A range in which the component is 0.2 to 20 moles, preferably 0.5
It is preferable to set the amount within a range of 5 to 5 moles. In addition, if component c) is less than 0.1% by weight based on component g2, the effect of its addition will be insufficient, and if it is more than 10% by weight, the curability of this composition, the adhesion to the base material, etc. Since the residual adhesiveness of the silicone film decreases, the amount should be in the range of 0.1 to 10% by weight, preferably in the range of 0.5 to 5.0%, and 2)
If the component is (a) less than 0.001% by weight, the catalytic effect will be insufficient, and if it is added more than 1.0% by weight, the catalytic effect will be constant, resulting in an economical disadvantage.
The range may be from 0.001 to 1.0%.

In addition, this composition can be used to extend the pot life if necessary.
For the purpose of suppressing the activation of platinum at room temperature, an activity inhibitor may be added, such as various organic nitrogen compounds, organic phosphorus compounds, and acetylene compounds. Furthermore, this composition may be used after being diluted with an organic solvent if necessary. Examples of the organic solvent include toluene-xylene-trichloroethylene, perchloroethylene, hexane, ethyl acetate-methyl ethyl ketone, and the like.

The silicone composition of the present invention is said to be particularly useful as a release agent for release paper; examples of this base material include kraft paper, polyethylene laminate paper, glassine paper, various other processed papers, and various plastic films. However, this composition can be applied to these substrates using a roll coater,
It may be carried out using a known method such as a gravure coater, an offset coater, or an air coater, and the coating film thus obtained may be heat-treated at 80°C or higher, preferably 100°C or higher for 10 seconds or more - preferably 20 seconds or more. , provides a cured coating with excellent mold release properties - this coating provides the benefit of no increase in release force, especially in high speed peeling.

Next, we will give an example of the present invention, where parts in the example are parts by weight, and viscosity is the value measured at 25°C6] - The physical property values in the example were measured by the following methods. It shows the value.

(Peeling force) A silicone composition was applied to high-quality paper laminated with polyethylene using an offset coater to give 0.8 g/W? Apply it evenly and heat cure it for 20 seconds in a hot air circulation dryer at 150°C to age the silicone film.
After standing at 5°C for 1 day, an acrylic solvent-based adhesive, Olypain BP, 8-8170 (trade name, manufactured by Toyo Ink Co., Ltd.) was applied to this at a solid content of 50g/- and heated to 100°C. After drying for 3 minutes, laminate it to high-quality surface paper.
After crimping with a 2Kp rubber roll once, it was heated to -25°C.
A test piece with a width of 50 mm was prepared by leaving it to stand for a day (1), and using a tensile tester (Ryuri Autograph and Toyo Seiki High Speed Peel Tester), the peel angle was 180°C and the peel speed was 0: l 60-180.
The peeling force was measured when the surface paper was peeled off at m/min.

′ (Curing properties, adhesion properties) The heat curing conditions for forming the silicone film above are as follows:
The silicone film obtained at 100℃ for 30 seconds was
The degree of curing was determined by the presence or absence of clouding when rubbed vigorously twice, and the degree of adhesion was determined by the presence or absence of the silicone coating falling off at this time.

(Residual adhesion rate) A commercially available kraft tape was pasted on the silicone-treated paper obtained by the peel force test method, and the tape was pressed at 70°C for 20 hours under a load of 20 g/d, and the standard adhesive strength was measured. In order to do this, a similar craft tape was attached to a Teflon plate and the same pressure bonding process was performed - the adhesive strength of each sample after this pressure bonding process was measured, and the adhesive strength of the craft tape bonded to the Teflon plate was taken as 100. Residual adhesion rate of one sample (%
) was sought.

Examples 1-5. Comparative Examples 1 to 6 100 parts of dimethylpolysiloxane containing 1 mol % of vinyl groups and having a viscosity of 3,000 centivoise (hereinafter abbreviated as OP) and 1.0 part of methylhydrodiene polysiloxane having a viscosity of 180 CP. and polyoxyalkylene group-containing organosiloxane 1.0 as shown in Table 1.
part and complex of chloroplatinic acid and vinylsiloxane 1.0
(0.002 parts in terms of platinum) was added and stirred uniformly to prepare a silicone treatment bath.

15 Next, use this processing groove on high-quality paper laminated with polyethylene and use an offset roll to add 0.8 g of silicone/
When the physical properties of the obtained silicone coating film were examined, the results shown in Table 2 were obtained.

In addition, for comparison, a siloxane containing a polyoxyalkylene group was added to the above (Comparative Example 1), and a siloxane containing a polyoxyalkylene group was added in an amount of 53% by weight. (Comparative Example 2), polyoxyalkylene group does not contain trifunctional siloxy group (Comparative Example 3), and polyoxyalkylene group content is 2% (Comparative Example 4) One containing no polyoxyalkylene group at all (Comparative Example 5), and no polyoxyalkylene group-containing siloxane added so that the peeling force at -0.3 m/min was the same as that of Example 1. When the physical properties of the silicone films obtained from these compositions were investigated (Comparative Example 6), the results shown in Table 2 were obtained.

Claims (1)

[Claims] 1. A) General formula R^1_aR^2_bSiO_[_4_
−_(_a_+_b_)_]_/_2 (here, R^1 is a monovalent aliphatic unsaturated hydrocarbon group, R^2 is the same or different unsubstituted or substituted monovalent hydrocarbon group, a, b is a positive number, a+b≦3) 100 parts by weight of organopolysiloxane b) General formula R^3_cH_dSiO_[_4_-_(_
c_+_d_)_]_/_2 (where R^3 is the same or different unsubstituted or substituted monovalent hydrocarbon group, c and d are positive numbers and c+d≦3) organohydrodiene polysiloxane 0. 1 to 10 parts by weight c) General formula (SiO_2)_e(R^4_2SiO)_f(R^4
R^5SiO)_g(R^4SiO_1_._5)_h
[Here, R^4 is the same or different unsubstituted or substituted 1
The valent hydrocarbon group, R^5, has the formula -(CH_2)_nO(C_2H_4O)_i(C_3
H_6O)_j-Polyoxyalkylene group represented by R^6 (R^6 is a hydrogen atom or a monovalent organic group), e is 0 to 5, f is 0 to 200, g is 1 to 10, h is 1 ~20, i is 1-50, j is 0-50, n is 0-5
, m is a positive number of 1 to 4] 0.1 to 10 parts by weight of an organopolysiloxane containing 3 to 50% by weight of a polyoxyalkylene group in one molecule d) Platinum or a platinum compound 0.001 to 1 .0 parts by weight of a silicone composition for mold release.