JP3075684B2 - Aqueous release agent composition for cold cure polyurethane foam molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aqueous release agent used for molding semi-rigid and rigid polyurethane foams. More specifically, the present invention relates to an aqueous release agent composition for cold-cured polyurethane foam molding, which is used at a mold temperature of 20 to 60 ° C. for curing.

[0002]

2. Description of the Related Art When molding semi-rigid polyurethane foams such as armrests, headrests, crush pads, etc., a composition containing various waxes or silicones or petrolatum or a hydrocarbon oil, alone or in combination, is mixed with low boiling gasoline or chlorinated gasoline. What is dissolved or dispersed in a solvent is used as a release agent.

[0003]

However, since such a release agent uses a volatile organic solvent, there is a problem of fire danger and work environment. In order to improve such problems, development of an aqueous release agent is desired. Wax emulsions are already used for flexible hot-cure polyurethane foams and high-elastic polyurethane foams.However, if these release agents are used for molding semi-rigid polyurethane foams, the release agents will be poor and practical poor. An object of the present invention is to improve the disadvantages of these aqueous release agents and to provide an aqueous release agent having performance not inferior to that of a solvent system.

[0004]

Means for Solving the Problems To achieve the above object, the present inventors have made intensive studies and found that a low melting point wax emulsion was mixed with a silicone oil emulsion or an amino-modified silicone emulsion, or that a wax was mixed with a wax. By using a composition obtained by emulsifying a mixture of silicones according to a conventional technique, a molded article has a good finish, and it has been found that the release agent is excellent, and the present invention has been completed.

That is, the present invention relates to (a) melting point of 40 to 9
A wax emulsion having a penetration of 7 to 150 at 0 ° C. and 25 ° C., especially a wax emulsion in which microcrystalline wax, polyethylene wax or paraffin wax is emulsified alone or mixed with a volatile amine salt of a commercial grade higher fatty acid; b) The viscosity of the base oil is 10 to 2000 mPa. s (at 20 ° C.) dimethyl silicone emulsion or amino equivalent of 300
An aqueous release agent composition for forming a cold-cured polyurethane foam comprising an aqueous emulsion containing a silicone emulsion alone or mixed with an amino-modified silicone emulsion of 0 to 25000 as an essential component. In addition, an antioxidant, petrolatum, carbonized Hydrogen oil,
An aqueous release agent composition for cold-cured polyurethane molding, comprising a wetting improver, an oxidized wax, an ester wax and the like as optional components. Here, the solid content concentration of the aqueous release agent composition is preferably 2 to 40% by weight. If the amount is less than 2% by weight, the releasability is deteriorated due to insufficient solid content, and if the amount is more than 40% by weight, excess mold release agent accumulates in the mold and mold stains are large, which is uneconomical. By mixing the component (a) and the component (b) at an arbitrary ratio within a solid content range of 2 to 40% by weight, an aqueous release agent composition having performance not inferior to that of a solvent system can be obtained. In particular, when the ratio of the wax of the component (a) to the silicone of the component (b) is in the range of 1: 4 to 4: 1, the synergistic effect of the wax and the silicone is remarkable, and both the releasability and the finish are excellent. It becomes an aqueous release agent composition. Hereinafter, the components of the composition of the present invention will be described.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Wax emulsion The wax emulsion used in the present invention has a melting point of 40.
It is preferable to emulsify a non-polar wax such as polyethylene wax or microcrystalline wax or paraffin wax having a penetration of 7 to 150 at 25 ° C. at a temperature of up to 90 ° C. For the emulsification, it is preferable to emulsify these waxes alone or as a mixture using a volatile amine salt of a higher fatty acid. Here, it is not preferable that the melting point of the wax exceeds 90 ° C., because the releasability is reduced and mold stains increase. On the other hand, if the melting point is less than 40 ° C., the urethane surface is not preferable because the cells are roughened or depressed. In addition, a wax having a large penetration is likely to cause cohesive failure and improve the releasability.
Exceeding the range is not preferable because the urethane surface tends to roughen or collapse the cells. A hard wax having a penetration at 25 ° C. of less than 5 is not preferable because mold releasability is lowered and mold stains are increased.

Silicone oil emulsion The dimethyl silicone emulsion used in the present invention has a base silicone oil having a viscosity of 10 to 2000 mPa.
Those using s (at 20 ° C.) are preferred. Viscosity is 1
If it is less than 0 mPa · s (at 20 ° C.), the molded article becomes rough or depressed, and if it exceeds 2000 mPa · s (at 20 ° C.), it does not contribute to the releasability.

Amino-modified silicone emulsion The amino-modified silicone emulsion used in the present invention is generally represented by the following general formula I and is prepared by a conventional method. It is considered that the reaction between the amine and the urethane promotes the curing of the urethane and improves the releasability. Therefore, those having an amino equivalent of 3000 to 25000 are preferable. If the amount is less than 3,000, the amount of amine is excessive and the accumulated matter in the mold tends to be resinified. If the amount exceeds 25,000, the effect is hardly recognized due to the insufficient amount of amine, which is not preferable.

Formula I

Embedded image

Other Ingredients In addition to the above essential ingredients, additives such as conventional wetting improvers and antioxidants which have been used in conventional release agents, oily substances such as hydrocarbon oils and petrolatum, and oxidized waxes An ester wax can be added as an optional component.

Production Method A method for producing the release agent composition of the present invention is, for example, as follows. That is, first, the wax component is 100-
The mixture is heated and melted at 120 ° C., and gradually added to an aqueous solution of an aliphatic amine salt heated to 90 ° C. or higher while stirring. In this way, a pre-emulsion having a solid content of 10 to 40% by weight is prepared and then homogenized to make emulsion particles fine. The 90 thus obtained
A stable wax emulsion composition is prepared by rapidly cooling the emulsion at a temperature of not less than room temperature to a temperature close to room temperature (see JP-A-06-226755). A stable release agent composition is prepared by sufficiently stirring and mixing a commercially available silicone emulsion or amino-modified silicone emulsion in consideration of ionicity with the wax emulsion thus produced. Or, by emulsifying a mixture of a wax component, a silicone component and a nonionic surfactant according to the above-described production method,
A stable release agent composition is obtained.

The above composition is diluted with water to prepare a release agent having a solid content of 2 to 40%. After air spraying on a mold at 20 to 50 ° C., water is dried and urethane foam raw material is injected. After curing for a certain period of time, the mold is released from the mold. A conventional airless or air gun can be used for application, but a low-pressure atomizing gun or a hot-air low-pressure coating gun is effective in consideration of the drying property and wettability of water.

[0013]

Next, the present invention will be described with reference to examples. However, the following examples do not limit the present invention at all. Parts and% in the examples represent parts by weight and% by weight, respectively. Tables 1 and 2 show basic compositions, characteristic values, and the like of the wax emulsion and the silicone emulsion used in the following Examples and Comparative Examples.

[0014]

[Table 1]

[0015]

[Table 2]

Examples 1 to 6 A wax emulsion and a silicone emulsion or a silicone emulsion (amino-modified emulsion) shown in Table 1 were blended according to the formulation shown in Table 3 below.

[0017]

[Table 3]

Comparative Examples 1 to 11 Wax emulsions and silicone emulsions shown in Tables 1 and 2 were blended in accordance with the formulations shown in Tables 4 and 5 below.

[0019]

[Table 4]

[0020]

[Table 5]

(Note 1) to (Note 9) in Tables 1 and 2 are collectively shown in Tables 6 to 8 below.

[0022]

[Table 6]

[0023]

[Table 7]

[0024]

[Table 8]

Performance Evaluation Test In order to clarify the effect of the aqueous release agent for molding the semi-rigid polyurethane foam of the present invention, the following performance evaluation was performed on the compositions of Examples and Comparative Examples. Test items and test methods are shown below, and the results are shown.

(1) Application of release agent An iron mold (length: 350 mm , width: 110 mm ,
(Height: 23 mm , thickness: 3 mm ) is adjusted to 35 ± 3 ° C., and is evenly (approximately 30 g / m ² ) applied with a release agent (solid content: 10%) using an air gun and dried.

(2) Molding of semi-rigid polyurethane foam Raw material of urethane foam: A / B = 2/1 (RM-1018-2 manufactured by Nippon Polyurethane Chemical Co., Ltd., where A is a polyol and B is an isocyanate) Was stirred at 20 ° C. and 3000 rpm for 6 seconds, and poured into a mold at 35 ° C., and the lid was closed. The reaction was completed by curing in an oven at 40 ° C. for 6 minutes.

(3) Evaluation of Releasability After removing the lid of the mold, the releasability was evaluated by touching with a finger. Evaluation Criteria ○: Can be taken with a slight force △: Can be taken with a little force ×: It is difficult to remove even if force is applied, or the material breaks

(4) Finish of Molded Foam Surface Roughness of the molded foam surface was visually observed. Evaluation criteria ○: Indicates no cell roughness or depression △: Indicates partial cell roughness or depression ×: Indicates that cell roughness or depression is severe

[0030]

[Table 9]

[0031]

[Table 10]

[0032]

[Table 11]

[0033]

The release agent of the present invention has remarkably improved releasability and good finish as compared with conventional aqueous release agents. Further, the following effects can be obtained by obtaining a release agent and finish comparable to the solvent type release agent. (1) Workability comparable to solvent type (2) Easy handling (3) Work environment is significantly improved (4) Excellent economy

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-226752 (JP, A) JP-A-58-45297 (JP, A) JP-A-3-288606 (JP, A) JP-A-4- 1006 (JP, A) JP-A-4-185310 (JP, A) JP-A-61-76324 (JP, A) JP-A-7-70547 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) B29C 33/56-33/66

Claims (1)

(57) [Claims] 1. A wax emulsion having a melting point of from 40 to 90 ° C. and a penetration at 25 ° C. of from 7 to 150, and a viscosity of (b) a base oil of from 10 to 2000 mPa.s. s
An aqueous release agent composition for forming a cold-cure polyurethane foam, comprising, as an essential component, a silicone emulsion containing a dimethyl silicone emulsion (at. 20 ° C.) or an amino-modified silicone emulsion having an amino equivalent of 3000 to 25000, alone or as a mixture.