JPS5932515B2 - Mold release agent for urethane resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold release agent for urethane resins, and particularly to a silicone mold release agent for urethane resins that has excellent mold release properties and can be used repeatedly.

Urethane resin is used in various fields due to its excellent chemical resistance, mechanical properties, and electrical properties, and this molding is mainly done by compression molding and injection molding. is particularly widely used for foams, which are produced by injection foaming in molds.

However, this resin has strong adhesion and stickiness, making it difficult to remove the cured molded product from the molding material.
This requires the use of a mold release agent. Various types of release agents have been used in the past, including various waxes with melting points at room temperature or around the molding temperature of urethane resin, organic solvent solutions of metal soaps or their aqueous dispersions, Fluororesin or silicone resin or their combination composition (Special Publication No. 5
3-123271), and furthermore, a composition comprising a wax and a silicone resin (Japanese Patent Publication No. 56-14714) is known.

However, this wax and metal soap have the disadvantage that they are difficult to peel off, and because they are solid, they accumulate on the mold soil when used repeatedly, causing so-called mold scum, and staining equipment and the floor of the workshop. Similar disadvantages apply to compositions consisting of silicone resins and silicone resins. In addition, those using fluororesin still suffer from heavy peeling and are expensive, which is disadvantageous in terms of economy. For this reason, as this type of mold release agent, those using silicone resin alone are attracting attention, but since the mold release properties of dimethylpolysiloxane alone, which is the most common silicone resin, are insufficient, Power method using carboxy-functional siloxane (see Japanese Patent Publication No. 55-1176), polyether-modified siloxane, triorganosiloxy unit and Si
A method of using an organosiloxane copolymer consisting of O units in combination (see JP-A-50-116558) has been proposed, but these are still insufficient in terms of releasability.
This improvement is desired. The present invention relates to a silicone-based mold release agent for urethane resins that has extremely light peeling and can be used multiple times after one application. has 1 or more carbon atoms
3, R5 is the same or different group selected from substituted or unsubstituted monovalent hydrocarbon groups having 1 to 6 carbon atoms, R4 is the same or different group selected from R5 or R3-NH'Zj)) A different group (R3 is a divalent hydrocarbon group having 1 to 5 carbon atoms), Z is a hydrogen atom, a monovalent hydrocarbon group, or an aminoalkyl group, and n is an integer of 1.0 or more.

It is characterized in that it consists of a diorganopolysiloxane represented by the following formula, in which both ends of the molecular chain are blocked with aminoalkyl/dialkoxysilyl groups. To explain this, as a result of various studies on silicone-based mold release agents, the present inventors have developed a release agent in which both ends of diorganopolysiloxane are blocked with an aminoalkyl group and a siloxy group having two alkoxy groups. When used as a molding agent, the coating surface exhibits extremely light releasability, and when applied inside the mold of a urethane resin molding machine, the surface has excellent durability and releasability sufficient to withstand repeated use. The present invention was completed by confirming that it forms a film and that it is also useful as a mold release agent for epoxy resins, which have strong adhesive properties like polyurethane.

The diorganopolysiloxane whose molecular chain ends are blocked with aminoalkyl/dialkoxysilyl groups (hereinafter referred to as aminoalkyl-modified diorganopolysiloxane as appropriate) is used as the main ingredient of the mold release agent for urethane resins of the present invention. Rl and R2 are represented by a methyl group, ethyl group, or propyl group, and R5 is an alkyl group.
is a monovalent hydrocarbon group having 1 to 6 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an alkenyl group such as a vinyl group or an allyl group, or a phenyl group;
Examples include groups in which the hydrogen atoms of these monovalent hydrocarbon groups are partially substituted with halogen atoms, cyano groups, and the like.
Further, R4 is a group selected from the above-mentioned R5 or -R3-NHZ. Examples of R3 include a methylene group, ethylene group, and propylene group, and examples of Z include hydrogen groups as well as the above-mentioned alkyl groups, alkenyl groups, aryl groups, aminoalkyl groups, and the like. This aminoalkyl-modified diorganopolysiloxane is made from, for example, a hydroxylated diorganopolysiloxane having a hydrogen group bonded to a silicon atom at both ends of its molecular chain, and an organosilane containing an aminoalkyl group and an alkoxy group as starting materials. , can be easily produced by subjecting a mixture of these to a dealcoholization condensation reaction, but this usually has a concentration of 50 to 150
This can be carried out by dropping the hydroxylated diorganopolysiloxane into a diluted solution of the organosilane mentioned above maintained at a temperature of The reaction may be carried out in an organic solvent in the presence of an organic metal salt such as tin or zinc, or a catalyst such as an amine, which is added as necessary. This hydroxylated diorganopolysiloxane is obtained by polymerizing low-molecular cyclic substances such as cyclomethylcyclotetrasiloxane and octaphenylcitalotetrasiloxane in the presence of an alkali catalyst, and it cures at room temperature. Since it is used in large quantities as a base oil for synthetic liquid rubber and construction sealant materials, it can be obtained easily and at a relatively low cost. (CH
3O) 3Si (CI- [2) 3NH2, ~υ▲53υノ＼(ノz▲10υノy＆＼v roar Z′Z▲1▲breath Z
ll(CH3O)3S1(CH2)3NHCH2CH2
This reactant can be produced at a relatively low cost since it may be a known product such as NH2.

The reaction product is used as a mold release agent after removing the alcohol produced as a by-product and the organic solvent used as a diluent, and then mixed with an appropriate solvent or other components as necessary. Examples of this solvent include toluene, xylene, methylene chloride, trichloroethane, trichloroethylene, ligroin, kerosene, rubber volatile oil, etc., but these solvents can also be used with nonionic, anionic, or cationic general emulsifiers. It can also be used dispersed in water. The aminoalkyl-modified diorganosiloxane mold release agent of the present invention can be used alone as a mold release agent for polyurethane resins in the form of the above-mentioned solvent solution or emulsion, but this is different from other conventionally known silicone mold release agents. agents, such as dimethylpolysiloxane with both ends capped with trimethylsiloxy groups, dimethyldiphenylpolysiloxane, hydroxylated dimethylpolysiloxane with hydroxyl groups on both ends, and compounds with the general formula (R
3SiOl/2) May be used together. Next, examples of the present invention will be given.
However, in the following description, all parts simply refer to parts by weight. Example 1 2t equipped with cooler, thermometer, dripping device and stirring device
Trimethoxyaminopropylsilane 1 in a round bottom flask
59, toluene 4009 and dibutyltin dilaurate 0.89 as a catalyst were charged, mixed uniformly, and heated to an internal temperature of 100°C.

Next, dimethylpolysiloxane 8, which has a viscosity of 1000 cS at 25°C and is blocked at both ends with hydroxyl groups, is added to this.
A mixture of 009 and toluene 2009 was added dropwise over 1.5 hours, and after the addition was completed, heating and stirring were continued for an additional 4 hours. After the reaction is complete, 1011i1! 60 under reduced pressure of THg
When toluene and the alcohol produced therein were removed at ℃, an aminoalkyl-modified diorganopolysiloxane (hereinafter abbreviated as siloxane A) having a viscosity of 2100 cS and having two methoxy groups and two aminopropyl groups at both ends was obtained. )was gotten. Next, industrial gasoline is blended with Siloxane A and/or dimethylpolysiloxane whose end is capped with a trimethylsiloxy group and has a viscosity of 1000 cS at 25°C (hereinafter referred to as Siloxane B) to form a mold release agent. This was applied by air spray to an epoxy FRP board serving as a polyurethane foam molding frame, and a semi-rigid polyurethane foam composition having the following composition was poured into the molding frame, and heated at 60°C.
After heating and curing for 30 minutes, the cured polyurethane was peeled off from the epoxy FRP board, and the results shown in Table 1 were obtained.

Example 2 N-β(
16.79 g of γ-aminopropyl-trimethoxysilane (aminoethyl) and 500 g of toluene were charged, mixed uniformly, and heated to 100°C to obtain 500 f of dimethylpolysiloxane with a viscosity of 700 cS, both ends of which were blocked with hydroxyl groups! A mixture of toluene 1009 and toluene 1009 was added dropwise over 1 hour, and after the addition was completed, heating and stirring was continued for 4 hours, and toluene and by-product alcohol were removed. As a result, two methoxy groups and N-β (amino An aminoalkyl-modified diorganopolysiloxane (hereinafter abbreviated as siloxane C) having a viscosity of 1500 cS and having (ethyl)γ-aminopropyl groups was obtained.

On the other hand, for comparative testing, decamethyltetrasiloxane 1
5.59, octamethylcyclotetrasiloxane 110
09 and N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane 169 were heated and stirred with 0.39 potassium hydroxide at 140°C for 8 hours, and after the reaction was completed, this was neutralized with ethylene chlorohydrin 59. ,5w1tH
When low molecular weight substances were removed by heating to 140°C under reduced pressure of )was gotten. Next, industrial gasoline was added to these siloxanes C and D and the above-mentioned siloxane B to prepare a mold release agent composition, and when the same peelability test as in the previous example was conducted using this composition, the following second The results shown in the table were obtained.

Example 3 Siloxane A used in Example 1 or Siloxane D used as a comparative example in Example 2 and dimethylpolysiloxane with a viscosity of 1000 cS with both ends of the molecular chain blocked with hydroxyl groups (hereinafter abbreviated as Siloxane E). ) was mixed in equivalent amounts and dissolved in methylene chloride to prepare a mold release agent. Using these, a releasability test was conducted in the same manner as in the previous example, and the results are shown in Table 3 below. Obtained.

Example 4 Trimethylchlorosilane (CH3)3SiC1108.
59 and tetrachlorosilane SiCl4l7Og were mixed, and this was added dropwise to a system consisting of 10009 water, 1009 isopropanol, and 2009 toluene to cause cohydrolysis.
When the acid was neutralized by washing with water, a siloxane consisting of trimethylsiloxy units and SiO2 units (hereinafter abbreviated as siloxane F) was obtained.

Next, 1 part of this siloxane F and 2 parts of siloxane A obtained in Example 1 were mixed with 97 parts of methylene chloride to prepare a release agent, and when the same release test as in Example 1 was conducted using this, it was found that polyurethane The cured product could be peeled off very easily, and this remained the same even after repeated use.

Example 5 The same peelability test as in Example 1 was conducted on a mold release agent made by blending 95 parts of industrial gasoline with 2 parts of siloxane A used in Example 1 and 3 parts of siloxane E used in Example 3. For comparison, a similar releasability test was conducted on mold release agents whose main ingredients were perfluoroalkyl acrylate polymer, polyether-modified polysiloxane, and thiocarboxylic acid-modified polysiloxane with the following composition. The results shown are obtained.

0 Comparative Example 5-1 A 2% 1,1,1-trichloroethane solution of a perfluoroalkyl acrylate polymer that is solid at room temperature and has a fluorine content of 20%. Example 6 Trimethoxyaminopropylsilane 159, toluene 400
9 and dibutyltin dilaurate as catalyst 0.8
9 was charged, mixed uniformly, and heated to an internal temperature of 100°C.

Next, diorganosiloxane 8009, which has both ends blocked with hydroxyl groups and is composed of 90 mol% dimethylsiloxane units and 10 mol% diphenylsiloxane units and has a viscosity of 1,500 CS at 25°C, and toluene 4009 are added.
The mixture was added dropwise over 1.5 hours, and after the addition was completed, heating and stirring at 100° C. was continued for 5 hours. After the reaction is completed, 10? When toluene and the alcohol produced therein were removed at 60°C under the reduced pressure of the river, a viscosity of 3.2% was obtained, which had two methoxy groups and two aminopropyl groups at both ends, respectively.
A 500 cS aminoalkyl-modified diorganopolysiloxane (hereinafter abbreviated as siloxane G) was obtained. Next, industrial gasoline was added to this Siloxane G to prepare a mold release agent composition, and the same releasability test as in Example 1 was conducted using this composition, and the results were shown in Table 5 below. was gotten.

Example 7 Using the same equipment as in Example 1, 159% of trimethoxyaminopropylsilane and 400% of toluene were added to the flask.
9 and dibutyltin dilaurate as catalyst 0.8
9 was charged, mixed uniformly, and heated to an internal temperature of 100°C.

Next, diorganosiloxane 8009, which has both ends blocked with hydroxyl groups and is composed of 90 mol% dimethylsiloxane units and 10 mol% vinylmethylsiloxane units and has a viscosity of 1,000 cS at 25°C, and toluene 200 are added.
The mixture with 9 was added dropwise over 1.5 hours, and after the addition was completed,
Heating and stirring were further continued at 100° C. for 5 hours. After the reaction is completed, 10? When toluene and the alcohol produced therein were removed at 60°C under reduced pressure in Yu, 2
It has methoxy groups and aminopropyl groups, and has a viscosity of 2.
, 300 cS of aminoalkyl-modified diorganopolysiloxane (hereinafter abbreviated as siloxane H) was obtained. Next, industrial gasoline was added to this Siloxane H to prepare a mold release agent composition, and the same releasability test as in Example 1 was conducted using this composition, and the results were shown in Table 6 below. was gotten.

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R^1 and R^2 are alkyl groups having 1 to 3 carbon atoms,
R^5 is the same or different group selected from substituted or unsubstituted monovalent hydrocarbon groups having 1 to 6 carbon atoms, R^4 is R
Same or different groups selected from ^5 or -R^3-NHZ (R^3 is a divalent hydrocarbon group having 1 to 5 carbon atoms)
, Z represents a hydrogen atom, a monovalent hydrocarbon group, or an aminoalkyl group, and n represents a positive integer of 10 or more. A mold release agent for urethane resins, which is composed of a diorganopolysiloxane represented by the following formula, in which both ends of the molecular chain are blocked with aminoalkyl/dialkoxysilyl groups.