JP2001096542A - Aqueous mold release agent for urethane foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous mold release agent for a urethane foam having good mold releasability and small stain of a mold due to a deposit. SOLUTION: The aqueous mold release agent for a urethane foam is obtained by adding a monomer and a polymerization initiator to a wax emulsion type aqueous mold release agent. The wax emulsion type aqueous mold release agent is obtained by emulsion dispersing an wax or the like such as a polyethylene wax, an oxide wax, a natural wax, a liquid wax or the like in water by using a surface active agent. As the wax, a polyethylene oxide wax, or a paraffin wax is used. As the type of the surface active agent, a nonionic surface active agent is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an aqueous release agent for urethane foam.

[0002]

2. Description of the Related Art A general urethane foam foam molding process is generally described. In general, a stock solution obtained by mixing a polyol or polyether with a diisocyanate, a catalyst, a flame retardant, and the like at an appropriate ratio is injected into a mold. After the temperature is maintained at about 45 to 90 ° C. for 1 to 30 minutes, a step of taking out a molded product of the formed polyurethane foam is taken. Since polyurethane foam has an extremely strong adhesive property at the time of foaming, it is not easy to release a urethane foam obtained by foaming in a mold from the mold. For this reason, a method has been adopted in which a release agent is applied to the surface of a mold in advance to prepare the release.

[0003] Conventionally, as a release agent, for example, a wax or silicone oil dispersed or dissolved in an organic solvent such as N-hexane, 1,1,1-trichloroethane or naphtha has been used. However, since the above-mentioned release agent uses an organic solvent which has a flash point and is toxic to the human body, an emulsion-type aqueous release agent in which wax is dispersed in water has recently been provided.

[0004]

In the case of such an aqueous release agent, an emulsifier and water are contained in a release agent film formed on a mold, and the emulsifier and water react with urethane raw materials. It is said that the demolding performance decreases. actually,
The performance of the aqueous release agent for urethane foam is inferior to that of the solvent release agent. Also, the amount of deposits on the mold generated by repeating the molding is much larger than that of the solvent-based release agent,
For this reason, there is a problem that the number of times of cleaning of the mold increases and the working efficiency is poor. In other words, the present invention has good releasability,
It is another object of the present invention to provide an aqueous release agent that causes less contamination of the mold by deposits.

[0005]

SUMMARY OF THE INVENTION The present invention provides an aqueous release agent for urethane foam, characterized in that a monomer and a polymerization initiator are added to a wax emulsion type aqueous release agent and polymerized.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The wax emulsion type aqueous release agent referred to in the present invention is obtained by emulsifying and dispersing waxes such as polyethylene wax, oxidized wax, natural wax, and liquid paraffin in water using a surfactant. Say.
In the present invention, it is preferable to use a polyethylene oxide wax or paraffin wax as the wax and a nonionic surfactant as the type of the surfactant.

[0007] The emulsification method is a conventional method and does not particularly matter. Generally, it is achieved by mixing the components using a stirrer after mixing the components. The phase inversion emulsification method is preferred from the viewpoint of emulsification stability.

The wax emulsion type aqueous release agent includes:
Further, additives such as a wax wetting improver, a rust preventive, and an antioxidant may be appropriately added.

The monomer used in the present invention is a polymerizable monomer, and particularly preferably a monomer which undergoes radical polymerization. Examples include styrene, methacrylate, methyl methacrylate, vinylbenzene, triallyl trimellitate, triallyl cyanurate and the like. Preferably, it is a styrene monomer. Further, copolymerization of different monomers may be used.

The amount of the monomer used in the present invention is 1 to 10 parts by weight based on 100 parts by weight of the wax used in the wax emulsion type aqueous release agent. If the amount is less than 1 part by weight, the effect of improving the releasability will not be obtained, and if it is more than 10 parts by weight, the polymer will have an adverse effect and the releasability will decrease. Preferably, the amount is 3 to 8 parts by weight based on 100 parts by weight of the wax.

The polymerization initiator according to the present invention is a catalyst for polymerizing a monomer. As the radical polymerization initiator,
Examples thereof include potassium persulfate and a diazo-based polymerization initiator. Preferably, it is a water-soluble diazo-based polymerization initiator. For example, 2,2`-azobis [2-methyl-N- (2-humanoxyethyl) fluoroamidite], 2,2`-asobisisobutylamide, 2,2`-asobis
{Methyl-N- [1,1`-bis (human peroxyethyl) ethyl] fluoroamidite} and the like.

The amount of the polymerization initiator used in the present invention may be an amount capable of polymerizing the monomer, but is generally 0.1 to 1% by weight of the monomer. Also, those containing an acid group such as sulfonic acid require caution because a large amount of the sulfonic acid or the like may corrode the mold or the like during application of the mold.

The method for preparing an aqueous release agent of the present invention is achieved by adding a predetermined amount of a monomer and a polymerization initiator to a wax emulsion-type aqueous release agent and stirring to polymerize the monomer. Generally, after adding a monomer and a polymerization initiator to the emulsion, the liquid temperature is raised from 60 ° C to 90 ° C.
To keep. The stirring may be such that the liquid flows slowly. Under these conditions, a polymerization reaction is carried out for 1 to 6 hours to produce a polymer. When styrene is used as the monomer, polymerization is preferably performed at a liquid temperature of about 90 ° C. for about 3 hours.

The method of using the aqueous release agent for urethane foam of the present invention can be carried out using the same equipment and conditions as when a solvent-based release agent is used. For example, a uniform film is formed by coating and drying on a mold heated to 45 ° C to 90 ° C. Thereafter, the urethane foam raw material may be injected into a mold, cured for 1 to 30 minutes, and then removed from the mold.

The coating amount of the aqueous release agent according to the present invention is 70 to 130 g / m 2 as an aqueous solution having a wax content of 10% by weight.
² . Preferably, a 90~110g / ^{m 2.} If the amount is small, the releasability is poor, and if the amount is large, it is not economically preferable.

[0016]

Next, the present invention will be described with reference to examples. However, the following examples do not limit the present invention in any way. [Examples 1 to 4] The water-soluble release agents of Examples 1 to 3 shown in Table 1 were prepared, and diluted with a 10% by weight aqueous solution of a wax component of the release agent as a test solution. The mold release performance (demolding force) test and the mold fouling test described in the above section were performed.

[0017]Release performance (demolding force) test  An aluminum mold (the molded product)
(Dimensions: 100 x 130 x 50 mm) with air gun
Apply uniformly and dry. The amount of application will be 3-4g
To do. Next, the urethane foam raw material shown below
After stirring and mixing at 3000 rpm for 5 seconds at room temperature,
Inject into mold and close lid. 1 minute in a 50 ° C oven
Cure to complete the reaction. Next, open the upper mold
The load (demolding force) (kg) required for removing was determined. 30 times
The average values are shown in Table 2. Raw material of urethane foam (semi-rigid urethane) ・ Isocyanate (WST1000 manufactured by Sanyo Chemical Co., Ltd.) 41 g ・ Polyol (WST2000 manufactured by Sanyo Chemical Co., Ltd.) 54 g

[0018]Mold stain test  The mold attached to the mold after performing the above-mentioned mold release test 30 times
The soil was collected and the amount was compared with the weight of the comparative example. result
Are shown in Table 2.

[0019]

[Table 1]

[0020]

[Table 2]

[Comparative Example 1 '] An aqueous release agent of Comparative Example 1' shown in Table 1 was prepared and diluted with a 10% by weight aqueous solution of a wax component of the aqueous release agent as a test solution. A test similar to the example was performed. The results are shown in Table 2.

[0022]

The aqueous release agent for urethane foam of the present invention does not contain a highly hazardous solvent, has good mold release properties, and has a small amount of deposits due to residues on the mold, so that the working efficiency is good. It is.

Claims (2)

[Claims] 1. An aqueous release agent for urethane foam, wherein a monomer and a polymerization initiator are added to a wax emulsion type aqueous release agent and polymerized. 2. The aqueous release agent for urethane foam according to claim 1, wherein the monomer is a styrene monomer.