JPS6317958A - Mold-releasing composition - Google Patents

Abstract

PURPOSE:To provide a mold-releasing composition composed of a polyorganosiloxane and polymethylsilsesquioxane powder and having high mold- releasing effect, low stickiness and excellent durability of the releasing effect. CONSTITUTION:The objective composition is produced by compounding (A) 100pts.(wt.) of a polyorganosiloxane preferably composed of (i) a polyorganosiloxane (silicone resin) composed of the unit of formula I or the unit of formula II, unit of formula III, unit of formula IV and unit of formula V (R<1> and R<2> are univalent substituted or unsubstituted hydrocarbon group, preferably methyl) and satisfying the formula VI and/or (ii) a polyorganosiloxane composed of the unit of formula II and the unit of formula V and containing 10-70wt% polyorganosiloxane wherein the amount of the unit of formula II is 0.4-1mol per 1mol of the unit of formula V and (B) 5-200pts. of a polymethylsilsesquioxane having an average particle diameter of 0.05-100mum, preferably 0.1-20mum, preferably produced by hydrolyzing methyltrialkoxysilane, etc., in an aqueous solution of ammonia.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a mold release composition, and more particularly to a mold release composition that maintains excellent mold release properties in molding of synthetic resins such as urethane resins.

[Technical background of the invention and its problems]

During pressure molding, injection molding, and other molding processes for industrial products such as rubber and plastics, separating materials are used to prevent these materials from sticking to the mother mold such as a mold and to make it easier to remove the molded product. Applying a molding agent is practiced. Polyorganosiloxane is suitable as a mold release agent because of its inherently low affinity with organic polymers, excellent heat resistance, and chemical inertness. It is well known that it is used in various industrial fields such as casting, pottery, paper, textiles, food, etc.

In addition to using polyorganosiloxane as a mold release agent as is, there are solution type silicones dissolved in organic solvents such as toluene, xylene, and mineral turpentine, and emulsion type silicones that are emulsified using an emulsifier and made into an aqueous solution. It is also well known that oil compound type compositions containing inorganic powders such as finely powdered silica, and aerosol type compositions in which a liquid such as 1.1.1-trichloroethane is added to a polyorganosiloxane or oil compound type composition are also used. There is.

In addition, as the polyorganosiloxane that becomes the base oil,
Generally, polydimethylsiloxane called methyl-based oil is often used, but depending on the application, polysiloxane containing 7-aryl groups such as phenyl group in addition to methyl group as an organic group bonded to the silicon atom, β-phenylethyl It is also known to use polysiloxanes containing aralkyl groups such as groups.

Although these polyorganosiloxanes have excellent mold release properties, they have drawbacks such as the persistence of mold release effect per application, low durability, and stickiness, so various methods have been developed to improve them. It is considered. for example,
JP-A-52-17323, JP-A-52-1732
Publication No. 4 discloses a method using a curable silicone resin, but since it is curable, there are problems in that it tends to leave residue on the mold and that it is necessary to use a curable catalyst.

On the other hand, JP-A-60-12248 discloses that oil-like polysiloxane and varnish-like polysiloxane are used together as polyorganosiloxane, and silica powder and alumina powder are used as inorganic powders in the form of a solution. Methods have been proposed to prevent stickiness and maintain mold releasability. However, in this method, inorganic powder is used for the purpose of preventing stickiness, so there is a problem in that the inherent mold release properties of silicone and the sustainability of varnish-like polysiloxane are deteriorated to some extent.

[Purpose of the invention]

An object of the present invention is to provide a mold release composition that has an excellent long-lasting mold release effect, is resistant to stickiness, and has excellent workability.

[Structure of the Invention] As a result of studying a mold release composition that solves these problems, the present inventors have found that by using polymethylsilsesquioxane powder as the powder, the durability of the mold release effect and the workability can be improved. It was discovered that a composition with excellent properties could be obtained, and the invention was thus completed.

The present invention consists of the following: (A) 100 parts by weight of polyorganosiloxane (B)
) A mold release composition characterized by comprising 5 to 200 parts by weight of polymethylsilsesquioxane powder having an average particle size of 0.05 to 100 μ.

The polyorganosiloxane of component (A) in the present invention serves as a base polymer in the present invention. Such a polyorganosiloxane, so-called silicone oil, is composed of terminals consisting of HOR12SiO□ units or R'3SiO□ units, and siloxane units other than the terminals are 90 to 100% R2□SiO units and the remaining R'', SiO A linear or branched liquid polyorganosiloxane consisting of y units (where a is 0 or 1) (where RI and R2 are each the same or different monovalent substituted or unsubstituted hydrocarbon group, and 50 to 9 in the total polyorganosiloxane
7% by weight): )IOR' gSiO□ units or R13SiO□ units, R", SiO units, R"5
Consisting of i03 units and SiO2 units, (R"+R"
)/5i=1.0 to 1.7, so-called silicone resin; SiO□ unit and R', SiO
It consists of units represented by □ units, R13SsO□ units are present in 0.4 to 1.0 mol per 1 mol of Sin, and 0.0004 to 1 hydroxyl group is bonded to each silicon atom. Examples include organosiloxane.

Here, the organic groups R1 and R2 to be bonded to this polyorganosiloxane include methyl group, ethyl group, propyl group, butyl group, amyl group, hexyl group, octyl group,
Alkyl groups such as decyl groups; alkenyl groups such as vinyl groups;
Aryl group such as phenyl group; β-phenylethyl group, β
Examples include aralkyl groups such as -phenylpropyl groups, and those in which some of their hydrogen atoms are substituted with chlorine atoms, fluorine atoms, nitrile groups, etc.

Among these, it is preferable that 90 mol% or more of R1 and RZ is a methyl group because it can be easily synthesized, and R1
More preferably, all of the groups are methyl groups.

Such polyorganosiloxanes can be synthesized by well-known methods. For example, in the case of silicone resin, triorganochlorosilane, diorganodichlorosilane, organotrichlorosilane, and tetrachlorosilane, and in the case of polyorganosiloxane consisting of R13SiO□ units and SiO□ units, the corresponding triorganochlorosilane and tetrachlorosilane, It can be obtained by blending in a stable amount and hydrolyzing and condensing the mixture in an aqueous solution containing a solvent such as toluene as required in the presence of an alkali catalyst or the like.

Moreover, as these polyorganosiloxanes, it is possible to use only what is called silicone oil, or to use silicone oil and silicone resin and/or R13S.
Any mixture of polyorganosiloxane consisting of iO□ units and SiO□ units may be used, but for the purpose of sustaining the mold release effect, silicone resin and/or a polyorganosiloxane consisting of R13SiO units and SiO□ units may be used. The total amount of organosiloxane is (A) 10 to 70 of the total weight
% is preferable.

Further, the viscosity of the component (A) is not particularly limited depending on the combination with the component (B), but it is preferable that the viscosity at 25° C. be 20 cSt or more in view of effects such as mold releasability.

Polymethylsilsesquioxane, the component (B) used in the present invention, is essential for imparting mold release properties to the composition, improving the sustainability of the mold release effect, and reducing stickiness. It is a component of This filler has a lower specific gravity when made into a compound than other silica-based fillers with similar average particle sizes, such as crushed quartz and diatomaceous earth, so even if it is filled in a large amount, the specific gravity of the system will not be too high. (In addition, the system exhibits little increase in viscosity and is highly fluid.Especially when the mold release composition of the present invention is stored for a long period of time as a solution, although sedimentation is observed, there is no aggregation, and the composition is lightly shaken. It has the characteristic that it can be redispersed extremely easily by simply adding the powder.This is compared to the case where ordinary powders used for similar purposes tend to settle and agglomerate after long-term storage, making redispersion impossible. That's a big advantage.

Polymethylsilsesquioxane is obtained by hydrolyzing and condensing methyltrialkoxysilane and/or its hydrolyzed condensate in an aqueous solution of ammonia or amines. It is preferable because it has almost no impurities such as, is spherical, and has excellent free-flowing properties. The particle size of polymethylsilsesquioxane is 0.05 to 100μ, preferably 0.1 to 2
It is 0 μ so. If the sheath is less than 0.05 μl, it is difficult to manufacture, and if it exceeds 100 μl, the mold release effect and the smoothness of the mold release surface will be impaired, making it impossible to obtain the functions necessary for the present invention.

The amount of (B) used is 5 to 5 per 100 parts by weight of (A).
00 parts by weight. If the amount used is less than 5 parts by weight, the mold release effect will be small (and stickiness will increase), and if the amount used exceeds 500 parts by weight, the composition will have poor workability.
This is also because when it is made into a solution type, it becomes difficult to dissolve.

Although the composition of the present invention exhibits its effects only with components (A) and (B), it may be further dissolved in an organic solvent to form a solution type. Examples of organic solvents in this case include gasoline, petroleum benzine, mineral spirits, toluene,
Examples include xylene, trichloroethylene, carbon tetrachloride, methylene chloride, and acetone.

In addition to the above-mentioned essential components, the composition of the present invention may optionally contain a thixotropic agent such as Aerosil, an antifoaming agent, a thermoplastic polymer such as paraffin wax or polystyrene, and the like.

The composition of the present invention is prepared by dispersing component (A), component (B), and optionally additives using a device such as a sand mill, three-roll mill, or ball mill, and mixing them uniformly. Moreover, when the composition is made into a solution type as required, the composition and the solvent may be uniformly mixed by stirring in an appropriate device such as a drum.

The composition of the present invention is applied to a mold by any method such as brush coating or spray coating, and the material is poured into the mold, followed by pressure molding.
Used as a mold release agent when molding by compression molding or other methods as required.

[Effects of the Invention] According to the composition of the present invention, it is possible to provide a mold release agent with a strong mold release effect (less stickiness) and excellent long-lasting mold release. By using a polyorganosiloxane consisting of SiO2 units and SiO2 units, the possibility of migration of silicone oil to the resin to be molded reduces adverse effects.Therefore, the composition of the present invention can be used to release molds of plastics such as rubber and polyurethane. It can be used as an agent in a wide range of applications.

〔Example〕

The present invention will be explained below with reference to Preparation Examples and Examples. The following abbreviations will be used below for brevity.

[Abbreviation] Me:C)l.

M: Me3SiO, unit D: MezSiO unit T: MeSiO+, s unit Q: SiO□ unit All "parts" in the examples indicate parts by weight. Also, D unit and Q
Polyorganosiloxanes consisting of units are represented by the following abbreviations.

S-1: 50% toluene of a resinous copolymer consisting of Q units and M units, the ratio of M units to 1 mole of Q units is 0.65 moles, and the hydroxyl group is bonded to the silicon atom. solution.

S-2: 50% of a resinous copolymer consisting of Q units and M units, the ratio of M units to 1 mol of Q units is 0.55 mol, and hydroxyl groups and ethoxy groups are bonded to silicon atoms. Triene solution.

S5-3 = unit, consisting of D unit, T unit and Q unit, molar ratio of M:I):T:Q unit is 30: 5: 55
A 50% toluene solution of a resinous copolymer having: 10.

Preparation Example 1 (Production of polymethylsilsesquioxane) 500 parts of water and 50 parts of an ammonia aqueous solution with a concentration of 28% were charged into a four-bottle flask equipped with a temperature needle, a reflux device, and a stirrer. , 200 parts of methyltrimethoxysilane shown in Table 1 was added to about 40 parts of methyltrimethoxysilane while stirring.
It was gradually added dropwise over several minutes. The reaction temperature started at 10°C and reached 30°C at the end of the dropwise addition. Next, the mixture was heated with a mantle heater to reflux at 84°C, and stirring was continued at this temperature for about 1 hour. After cooling, the product precipitated in the flask is collected, washed with water, dried, and then pulverized to produce powdered polymethylsilsesquioxane (P-1, P -2) was obtained.

Chapter 1 Table In addition, the following five types of silicone oil were prepared.

A polydimethylsiloxane having a viscosity of 100 cSt at 25°C, in which both ends of F- are blocked with trimethylsilyl groups, and the remainder are dimethylsiloxane units.

F-2: Polydimethylsiloxane having a viscosity of 2.000 cSt at 25°C, with both ends blocked with trimethylsilyl groups and the remainder being dimethylsiloxane units.

F-3: Polydimethylsiloxane having a viscosity of 30.000 cSt at 25°C, with both ends blocked with trimethylsilyl groups and the remainder being dimethylsiloxane units.

F-4: Both ends are blocked with trimethylsilyl groups, the remaining 70 mol% is dimethylsiloxane units, 30 mol% is diphenylsiloxane units, and the viscosity at 25°C is 500
cSt polymethylphenylsiloxane.

F-5: Both ends are blocked with trimethylsilyl groups, and the remaining 60 mol% is dimethylsiloxane jN (L40 mol%
is a β-phenylethylmethylsiloxane unit 25
Polyorganosiloxane with a viscosity of 1.800 cSt at °C.

Example 1 Silicone oils F-1 to F-4, resinous polysiloxanes S-1 and S-2, polymethylsilsesquioxanes P-1 and P-2, and xylene were uniformly mixed in the proportions shown in Table 2. Compositions A-11 to A-18 of the present invention
And comparative example compositions B-11 to B-14 were obtained. In addition,
B-11, 8-14 is a comparative example using Aerosil 200 (fumed silica, manufactured by Nippon Silikani Co., Ltd.) instead of polydimethylsilsesquioxane, B-12 is a comparative example using crushed quartz, B- No. 13 is a comparative example containing no powder.

These compositions were uniformly applied by spray painting to a concave stainless steel mold with a diameter of 4 cm square and a depth of 6 mm. Next, 100 parts of TP-132 (polyester resin, manufactured by Dainippon Ink ■) and 1 part of Permec N (effect agent, manufactured by NOF ■) were mixed uniformly, and the polyester resin was poured into the treated recess. The molded article was removed from the mold after being left to stand at 25° C. for 2 hours to harden. This pouring and molding operation was repeated 5 times, and the mold releasability, stickiness of the treated product on the surface of the mold, and the solution were removed at 500 + * for 2 months.
The stability of this product was investigated when it was packed and stored in a bottle.

The results are shown in Table 2.

Book 1: Initial mold releasability depends on the condition when the first molded product is removed.

*2 In the mold releasability evaluation, molded products and molds with no abnormalities are rated ◎, ○, and △ in order, and × indicates those that stick to the mold.

*3 For stickiness, make sure there is no stickiness when you touch it.
○, △ in order, and × indicates large stickiness.

Book 4 The stability of a solution is ◎ if it is uniform even without shaking, ○ if it becomes uniform with gentle stirring, × if it becomes uniform after stirring the sediment considerably, and × if the sediment becomes uniform evenly. Items that remain without being changed are marked as XX.

Example 2 F-5, S-2, S-3, P-1 and methylene chloride were blended as shown in Table 3 to form compositions A-21 to A- of the present invention.
24 and Comparative Example Composition B-21°B-22 were obtained. Incidentally, B-21 and 8-22 are comparative examples in which polymethylsilsesquioxane was not used.

This composition was applied to the mold of Example 1 in the same manner. Then l? t145 (two-component polyurethane resin, manufactured by Kokusai Chemical ■) was mixed uniformly at a ratio of base resin/curing agent = 100/65 parts by weight, poured into the treated recess, and heated at 25°C for 1 hour. After leaving it for a while, it was removed from the mold. This pouring and molding operation was repeated 10 times, and the sustainability of the mold releasability was measured. Moreover, composition A-2 of the present invention
The stability of Samples 1 to A-24 was examined in the same manner as in Example 1, and all of them were light (they quickly became a homogeneous solution upon stirring).

Table 3

Claims (1)

[Scope of Claims] 1. A mold release product characterized by comprising (A) 100 parts by weight of polyorganosiloxane (B) 5 to 200 parts by weight of polymethylsilsesquioxane powder with an average particle size of 0.05 to 100 μm. Composition. 2 In the polyorganosiloxane (A), HOR^1_2SiO_1_/_2 units or R^1_
3SiO_1_/_2 units, R^2_2SiO units, R
Polyorganosiloxane consisting of ^2SiO_3_/_2 units and SiO_2 units, and (R^1+R^2)/Si = 1.0 to 1.7, and/or R^1_3S
Consists of iO_1_/_2 units and SiO_2 units, R^
Polyorganosiloxane in which 1_3SiO_1_/_2 units are 0.4 to 1.0 mol per 1 mol of SiO_2 units (here, R^1 and R^2 are monovalent substituted or unsubstituted carbonized compounds that are the same or different from each other) (representing a hydrogen group) is 10
70% by weight of the mold release composition according to claim 1. 3 90 mol% of the organic group bonded to the silicon atom of (A)
The mold release composition according to claim 1, wherein the above group is a methyl group. 4. The mold release composition according to claim 1, wherein (A) has a viscosity of 20 cSt or more at 25°C. 5. The polymethylsilsesquioxane powder (B) is obtained by hydrolyzing methyltrialkoxysilane and/or its hydrolyzed condensate in an aqueous solution of ammonia or amines. The mold release composition according to item 1. 6. The mold release composition according to claim 5, wherein (B) has an average particle diameter of 0.1 to 20 μm.