JPH0773854B2 - Release agent composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a release agent composition, and more particularly to a film-forming release agent composition suitable for an external mold release agent.

[0002]

2. Description of the Related Art In the process of molding various rubbers or thermosetting or thermoplastic resins into molded products such as rubber mats, rubber hoses, tires and other rubber products or plastic products by operations such as pressure molding and injection molding. A release agent is used to prevent the product from sticking to the mold and to facilitate removal of the molded product from the mold. Such mold release agents include an external mold release agent applied to a mold for use and an internally added mold release agent added to the inside of a molded product for use.

Generally, the external mold release agent is an emulsion obtained by emulsifying and dispersing in water using a solution or a surfactant in which a non-reactive silicone oil is dissolved in a volatile organic solvent. It is used by being applied to the mold surface.

[0004]

However, in such an external mold release agent (hereinafter simply referred to as a release agent), when the molded product is released from the mold, the mold release agent becomes a molded product. It is necessary to compensate for this because it adheres and moves from the mold,
There is a drawback that the amount of release agent used is large and it is uneconomical.

Also, since the mold release agent is frequently applied, the mold becomes heavily soiled, and the process of removing the stains occurs frequently, which complicates the process and lowers the durability of the mold. There is a drawback that the production cost of the molded product increases because a step of removing the release agent attached is required when coating the molded product in a later step.

On the other hand, in order to solve such a drawback,
For example, there has been proposed a silicone film-forming mold release agent that forms a film adhered to the mold surface, such as a mold release agent composition using an organosilazane siloxane polymer (for example, Japanese Patent Publication No. 3-11248). However, there is a defect that the durability of the coating film is not sufficient and the releasability is also insufficient.

[0007] The inventors of the present invention have made extensive studies in order to solve such drawbacks, and as a result, by using a release agent composition containing a silicone resin which forms a specific cured film and a phenyl group-containing organopolysiloxane, The present invention has been achieved by finding that good results can be obtained. Therefore, an object of the present invention is to provide a silicone film forming type release agent composition which is excellent in the durability of the coating film and is also excellent in the releasing property.

[0008]

The above objects of the present invention are as follows.
The following components (a) to (c) are each 0.1 to 50% by weight,
0.01-10% by weight, 99.89-50% by weight , and 49.89 % by weight or less if necessary, the following structural formula (Chemical Formula 3) (n in the formula) Is 3 to 7)

[Chemical 3] It was achieved by a release agent composition consisting of a cyclic dimethyl polysiloxane represented by

(A): R ¹ SiO _3/2 structural unit and R ¹
₂ SiO _2/2 structural unit (wherein R ¹ is one or more organic groups selected from saturated or unsaturated monovalent hydrocarbon groups having 1 to 18 carbon atoms) And
In addition, the molar ratio of R ¹ SiO _3/2 / R ¹ ₂ SiO _2/2 is 95.
/ 5 to 50/50 organic solvent soluble silicone resin.

(B): General formula (Chemical Formula 4) (wherein R ² is one or more organic groups selected from saturated or unsaturated monovalent hydrocarbon groups having 1 to 18 carbon atoms) And R ³
Is a hydroxyl group or a saturated or unsaturated monovalent hydrocarbon group having 1 to 18 carbon atoms, and a phenyl group is contained in an amount of 0.01 to 20 mol% in all the substituents of R ² and R ³ . . m
Is 40 to 20,000 on average. )

[0011]

[Chemical 4] A linear organopolysiloxane containing a phenyl group represented by: (C): An organic solvent capable of dissolving (a), (b) and the cyclic dimethylpolysiloxane component.

In the present invention, specific examples of R ^{1 in} the silicone resin as the component (a) include, for example, a methyl group,
Alkyl group such as ethyl group, n-propyl group, iso-propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, tetradecyl group, octadecyl group, cyclopentyl group, cyclohexyl group, etc. Examples thereof include aryl groups such as cycloalkyl groups, phenyl groups and tolyl groups, unsaturated hydrocarbon groups such as vinyl groups and allyl groups, and the like. From the viewpoint of surface lubricity, R ¹ preferably has a methyl group content of 90 mol% or more.

The silicone resin which is the component (a) is
It can be easily produced by cohydrolyzing the corresponding silane compound by a known method (for example, Double Nor, Silicone Chemistry and Technology, pp. 192 to 196 (1968)). For example, R ¹ SiCl ₃ and R ¹ ₂ S
It can be easily obtained by adding a solution of a mixture of chlorosilanes composed of iCl ₃ in an organic solvent to excess water or an aqueous alcohol solution to cause co-hydrolysis.

Since the silicone resin thus obtained generally contains 10% by weight or less of hydroxyl groups and a small amount of alkoxy groups, a condensation reaction occurs when the release agent composition of the present invention is heat-cured. And raises the hardness of the silicone coating. Further, the silicone resin can be condensed by heating in the presence of a condensation catalyst such as sodium or zinc hydroxide to improve the crosslink density and make a more stable resin.

In the present invention, a single silicone resin may be used or two or more kinds of silicone resins may be mixed and used. In this case, the R ¹ SiO _3/2 structural unit and the R ¹ SiO ₂ structural unit may be used.
Molar ratio of ₂ SiO _2/2 structural units (R ¹ SiO _3/2 /
R ¹ ₂ SiO _2/2) is required to be 95 / 5-50 / 50, the preferred range of molar ratio 90/10
70/30.

If the molar ratio is more than 95/5, the compatibility with the phenyl group-containing linear organopolysiloxane which is the component (b) decreases, so that a uniform release agent composition cannot be obtained, while 50 / If it is less than 50, the hardness of the silicone coating decreases, and the adhesion to a substrate such as a mold deteriorates, resulting in poor durability of the coating, which is not preferable.

In the present invention, the amount of the silicone resin as the component (a) is required to be 0.1 to 50% by weight, and particularly 1 to 10% by weight. preferable. If the blending amount is 0.1% by weight or less, the thickness of the silicone coating becomes too thin to obtain a durable silicone coating, and if it is 50% by weight or more, the silicone coating becomes too thick and the silicone resin Is hard to cure, and it becomes impossible to obtain a film having a uniform thickness.

Specific examples of R ^{2 in} the general formula (Formula 4 ) of the phenyl group-containing linear organopolysiloxane which is the component (b) are, for example, methyl group, ethyl group, n-propyl group and iso-propyl group. Group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, tetradecyl group, octadecyl group and other alkyl groups, cyclopentyl group, cyclohexyl group and other cycloalkyl groups, phenyl group, tolyl group, etc. And an unsaturated hydrocarbon group such as an aryl group, a vinyl group and an allyl group.

As a specific example of R ^{3 in} the formula ( 4 ), there can be mentioned a hydroxyl group in addition to the same groups as R ² .
In the present invention, it is necessary that the proportion of the phenyl group in all the substituents of R ² and R ³ is 0.01 to 20 mol%. When the phenyl group content is 0.01 mol% or less, the compatibility with the silicone resin as the component (a) decreases, and a uniform silicone coating cannot be obtained.
On the other hand, when it is 20 mol% or more, the lubricity of the surface of the silicone coating is lowered and the releasability is deteriorated.

In the release agent composition of the present invention, the compounding amount of the phenyl group-containing linear organopolysiloxane, which is the component (b), is required to be 0.01 to 10% by weight. , 0.1 to 5% by weight is preferable. When the content is 0.01% by weight or less, the surface smoothness of the silicone coating is lowered and the releasability is deteriorated.
When it is 10% by weight or more, the strength of the silicone coating is lowered and the durability of the silicone coating is deteriorated.

Further, in the present invention, from the viewpoint of improving the surface smoothness of the silicone coating, the above-mentioned structural formula ( Chemical Formula 3 ) (wherein n is 3 to 7) soluble in an organic solvent described later is further employed. The cyclic dimethyl polysiloxane shown is 49.8.
It is particularly preferable to add 9 % by weight or less. 49.8
It is not preferable to add 9 % by weight or more, because the surface slipperiness is not improved and it becomes uneconomical.

In the present invention, the organic solvent as the component (c) dissolves the silicone resin as the component (a), the linear organopolysiloxane containing phenyl groups as the component (b) and the cyclic dimethylpolysiloxane. It can be appropriately selected and used from among those obtained.

Specific examples of these organic solvents include linear or branched saturated hydrocarbons, ethers such as diethyl ether, dipropyl ether and dibutyl ether, methanol, ethanol, propanol and butanol. Examples thereof include alcohols such as benzene, aromatic hydrocarbons such as benzene, toluene, and xylene, and mixtures of two or more thereof.

In the present invention, the compounding amount of the organic solvent is required to be 99.89 to 50% by weight, but it is particularly preferably 99 to 90% by weight. When the compounding amount is 99.98% by weight or more, the thickness of the silicone coating on the mold surface becomes too thin to provide a durable coating, and when it is 50% by weight or less, the silicone coating becomes too thick. Since it takes a long time to cure and a coating having a uniform thickness cannot be formed, a molded product having stable dimensions cannot be obtained.

In the present invention, a catalyst may be further added in order to accelerate the reaction when the silicone resin is cured to form a silicone coating. Specific examples of the catalyst include salts of fatty acids with zinc, lead, cobalt, tin, iron, zirconium and the like, quaternary ammonium salts or alkoxylates of aluminum, titanium and the like with alcohols,
Various amines or salts thereof can be mentioned.

[0026]

EFFECT OF THE INVENTION Since the mold release agent composition of the present invention can form a silicone coating having excellent durability and mold releasability on the mold surface, the number of times the mold release agent is applied to the mold is reduced. Since it is possible to take out the molded product from the mold, the production efficiency in the molding process is improved.

[0027]

EXAMPLES The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention. Examples 1-8 and Comparative Examples 1-2. The following components were blended as shown in Tables 1 and 2 to obtain release agent compositions of Examples and Comparative Examples.

Component (a) Silicone Resin A: CH ₃ SiO _3/2 / (CH ₃ ) ₂ S
90% by weight of a toluene solution of 20% by weight of a silicone resin of io _2/2 = 88/12, and CH ₃ SiO _3/2 / (CH
₃ ) ₂ SiO _2/2 = _48/52 silicone resin 20 wt% toluene solution 10 wt% mixed solution (CH ₃ Si
O _3/2 / (CH ₃ ) ₂ SiO _2/2 = 84/16).

Silicone resin B: CH ₃ SiO _3/2 /
(CH ₃ ) ₂ SiO _2/2 = _88/12 Silicone resin 20% by weight toluene solution. Silicone resin C: CH ₃ SiO _3/2 / (CH ₃ ) ₂ S
20% by weight toluene solution of silicone resin of i0 _2/2 = 70/30.

Component (b) Phenyl group-containing polysiloxane (A): Phenyl group-containing polysiloxane A represented by the structural formula of (Chemical Formula 5) (phenyl group content is 5 mol%, viscosity is 3,000 cst
Is).

[Chemical 5]

Phenyl group-containing polysiloxane (B):
Phenyl group-containing polysiloxane B represented by the structural formula (Chemical Formula 6) (phenyl group content is 0.15 mol%, and the state is raw rubber).

[Chemical 6]

Phenyl group-containing polysiloxane (C):
Phenyl group-containing polysiloxane C represented by the structural formula (Chemical Formula 7) (phenyl group content is 5 mol% and viscosity is 1
00 cst).

[Chemical 7]

Phenyl group-containing polysiloxane (D):
Phenyl group-containing polysiloxane D represented by the structural formula (Chemical Formula 8) (phenyl group content is 2.0 mol%, and the state is raw rubber).

[Chemical 8]

Phenyl group-containing polysiloxane (E):
Phenyl group-containing polysiloxane E represented by the structural formula (Chemical Formula 9) (phenyl group content is 5.0 mol%, and the state is raw rubber).

[Chemical 8]

[0035]

[Table 1]

[Table 2] In addition, as the isoparaffin in the table, Isosol 400
(Trade name of Nippon Oil Co., Ltd.) was used.

The release agent compositions obtained in Tables 1 and 2 were
The dipping method was applied to a steel plate piece so that the thickness of the cured film was about 0.5 μm by the weight conversion method to form a film. Then, the coated steel plate piece was heated and dried at 150 ° C. for 1 hour to cure the coating film, and a test piece of the silicone coating type release agent was prepared. The results of evaluation of the obtained test pieces by the following tests are as shown in Table 3.

Evaluation test method Hardness of the film was evaluated by pencil hardness.

Lubricity of the coating 0.3 m of SBR rubber loaded with 200 g on the coating
The coefficient of kinetic friction when moving at a constant speed of 1 / min was measured by an autograph.

An adhesive tape (Lumirror 31B: trade name, manufactured by Nitto Denko Corporation) having a width of 2.5 cm was adhered to the releasable film, and pressure was applied to the tape with a roller having a load of 2 kg. And press the tape, and then press the tape at a constant speed (0.3 m
/ Min) and the force when peeled was measured. The smaller the measured values of the dynamic friction coefficient and the peeling force, the better the slipperiness and the releasability.

Mold release durability Rectangular rubber packing mold (molded product size: 3.8
× 6.8 cm, width 0.4 cm, thickness 0.3 cm), the mold release agent composition obtained in Table 2 was applied to the recessed rubber filling part, and the thickness of the cured film was about 1 by the weight conversion method. It is coated with paper gauze so that it becomes 0.0 μm, and then at 180 ° C. for 30 minutes.
A cured film was provided on the surface of the mold by heating and drying for minutes.

To this mold, 7.0 g of polyol-vulcanized fluororubber (Florel FC3009: trade name of Sumitomo 3M Co., Ltd.) was charged, and the pressure was adjusted to 15 by a high pressure press.
Vulcanize at 0 kg / cm ^{2 at} a temperature of 180 ° C. for 10 minutes,
A fluororubber molded product was obtained. The above rubber molding process was repeated, and the number of times (up to 20 times) until the molded product adhered to the mold and the smooth release operation could not be performed was measured and evaluated as the durability of the release film.

Comparative Example 3. Chlorosilane represented by the structural formula (CH ₃ ) SiCl ₃ (61.4% by weight) and the chlorosilane represented by the structural formula (Chemical Formula 10)

[Chemical 10] The 38.6 wt% mixture was reacted with ammonia to obtain a polymethylsilazane siloxane solution. The obtained solution was diluted with methylene chloride so that the concentration of polymethylsiloxane was 3% by weight to obtain a release agent composition.

Using the obtained releasing agent composition, a test piece was prepared in the same manner as in Example 1, and the same test as in Example 1 was conducted and evaluated. The results are as shown in (Table 3).

[Table 3]

[Chemical 9]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C08L 83/04 LRZ C10M 107/50 9159-4H // C10N 40:36 (72) Inventor Nakazato Morisan 1 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Silicon Technology Research Laboratories (72) Inventor Satoshi Kuwata 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Company Silicon Electronic Materials Research Laboratory

Claims (2)

[Claims] (A): R ¹ SiO _3/2 structural unit and R ¹
₂ SiO _2/2 structural unit (in the formula, R ¹ is one or more organic groups selected from saturated or unsaturated monovalent hydrocarbon groups having 1 to 18 carbon atoms) And R
¹ molar ratio of SiO _3/2 / R ¹ ₂ SiO _2/2 95/5
50/50 organic solvent soluble silicone resin
1 to 50% by weight, (b): General formula (Chemical formula 1) (R ² in the formula has 1 to 18 carbon atoms)
1 selected from saturated or unsaturated monovalent hydrocarbon groups of
Or two or more kinds of organic groups, R ³ is a hydroxyl group or a saturated or unsaturated monovalent hydrocarbon group having 1 to 18 carbon atoms, and a phenyl group is contained in all the substituents of R ² and R ^3. 0.01
~ 20 mol% is contained. m is an average value of 40 to 2
It is 10,000) A releasing agent composition comprising 0.01 to 10% by weight of a phenyl group-containing linear organopolysiloxane represented by the formula (c) and (c): 99.89 to 50% by weight of an organic solvent capable of dissolving the components (a) and (b). object. 2. The following structural formula (Chemical formula 2) (n in the formula is 3 to 7) which is soluble in an organic solvent (c). The release agent composition according to claim 1, which contains 49.89% by weight or less of the cyclic dimethylpolysiloxane represented by