阅读说明：本技术 脱模剂 (Release agent ) 是由 平松信志 于 2021-05-19 设计创作，主要内容包括：本发明的课题在于,提供一种成型品与模具的脱模性良好、成分向成型品上的转印少、成型品的粘接性良好的脱模剂。本发明的脱模剂包含将任意选择的两类烃系蜡的熔点之差为25℃以上的多类烃系蜡进行乳化而成的蜡乳液。(The invention provides a mold release agent which has good mold release performance between a molded product and a mold, less component transfer to the molded product and good adhesion of the molded product. The release agent of the present invention comprises a wax emulsion obtained by emulsifying a plurality of kinds of hydrocarbon waxes, wherein the difference between the melting points of two kinds of arbitrarily selected hydrocarbon waxes is 25 ℃ or more.)

1. A mold release agent comprising a wax emulsion obtained by emulsifying a plurality of types of hydrocarbon waxes, wherein the difference between the melting points of two types of hydrocarbon waxes selected from the hydrocarbon waxes is 25 ℃ or more.

2. The mold release agent according to claim 1, wherein the difference between the melting points is 90 ℃ or less.

3. A mold release agent comprising a wax emulsion obtained by emulsifying two types of hydrocarbon waxes having a difference in melting point of 25 ℃ or higher, wherein the weight ratio of the hydrocarbon wax on the high melting point side to the hydrocarbon wax on the low melting point side is 50/50 or more and 92/8 or less.

Technical Field

The present invention relates to a mold release agent, and particularly to a mold release agent suitable for producing a molded article such as a polyurethane resin having excellent mold release properties and adhesion properties.

Background

In the molding of a porous plastic foam such as a polyurethane resin, a mold release agent containing wax, silicone, or a mixture thereof as a nonvolatile component is used in order to facilitate the release of a molded product from a mold. Therefore, the components of the release agent are transferred from the mold to the surface of the molded article. The transfer component is chemically inactive, and its state is paste, oil or solid, and thus the adhesiveness of the molded product may be deteriorated. For example, in the production of a leather-covered steering wheel, when a leather material is adhered to a molded article, the adhesiveness may be insufficient due to a component of a release agent transferred to the molded article.

Examples of the pretreatment for improving the adhesiveness of the molded article include a sanding treatment with sandpaper, wiping with an organic solvent, and polishing. Patent document 1 discloses a method for bonding a porous plastic foam molded article, in which the bonding surface of the molded article is formed by mixing a silica powder and a solventWashing the composition to 1m per bonded surface²Adhering 1-10 g of silica, and then adhering with an adhesive.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4800811

Disclosure of Invention

Problems to be solved by the invention

Even when the pretreatment is performed, the release agent may not be removed, and the pretreatment is complicated, and therefore, it is desirable to bond the molded article without performing the pretreatment.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a mold release agent which has good releasability between a molded article and a mold, is reduced in transfer of a component to the molded article, and has good adhesion of the molded article.

Means for solving the problems

As a result of intensive studies, the present inventors have found that a release agent comprising a wax emulsion obtained by emulsifying two types of hydrocarbon waxes having a difference in melting point of 25 ℃ or more has good releasability between a molded article and a mold, and that the molded article has little transfer and good adhesion, and have completed the present invention.

That is, the release agent according to one embodiment of the present invention includes a wax emulsion obtained by emulsifying a multi-type hydrocarbon wax in which the difference between the melting points of two types of arbitrarily selected hydrocarbon waxes is 25 ℃ or more.

Here, the difference in melting points is obtained by performing DSC (Differential Scanning Calorimetry) on a mixture of two types of hydrocarbon waxes and obtaining the difference between 2 peaks of the obtained DSC curve.

Each of the two types of hydrocarbon waxes may contain one type of hydrocarbon wax, or may be a mixture of 2 or more types of hydrocarbon waxes.

The plurality of types of hydrocarbon waxes are two types or three or more types of hydrocarbon waxes.

In the release agent, the difference in melting point may be 90 ℃ or less.

The release agent according to one embodiment of the present invention includes a wax emulsion obtained by emulsifying two types of hydrocarbon waxes having a difference in melting point of 25 ℃ or higher, and the weight ratio of the hydrocarbon wax on the high melting point side to the hydrocarbon wax on the low melting point side is 50/50 or more and 92/8 or less.

Effects of the invention

According to the present invention, the releasability between the molded article and the mold is good, the transfer of the component to the molded article is small, and the adhesiveness of the molded article is good.

Drawings

Fig. 1 is a graph in which the relationships between the melting point difference and the mold release force, and between the melting point difference and the adhesion force were determined based on examples 3, 4, and 3 in which the weight ratio of the wax on the high melting point side to the wax on the low melting point side was the same.

Fig. 2 is a graph in which the relationship between the mold release force and the ratio of the hydrocarbon-based wax on the high melting point side to 100 wt% of the total amount of the hydrocarbon-based wax, and the above ratio and the adhesion force are obtained based on example 1, example 2, example 3, and comparative example 1, which have the same melting point difference.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The release agent according to one embodiment of the present invention includes a wax emulsion obtained by emulsifying a plurality of types of hydrocarbon waxes, wherein the difference between the melting points of two types of hydrocarbon waxes selected arbitrarily is 25 ℃ or more.

The hydrocarbon wax may be either a natural wax or a synthetic wax. Examples of the natural wax include mineral waxes such as animal and vegetable waxes and petroleum waxes. Examples of the petroleum wax include paraffin wax, microcrystalline wax, and vaseline. Examples of the synthetic wax include Fischer-Tropsch wax and polyethylene wax.

Each of the two types of hydrocarbon waxes may contain one of the hydrocarbon waxes described above, or may be a mixture of 2 or more types of hydrocarbon waxes.

When the difference between the melting points of the two types of hydrocarbon waxes is 25 ℃ or more, the releasability and adhesion of the molded article to the mold are good. This is considered to be because the film strength of the release agent becomes high by the hydrocarbon-based wax on the high melting point side, the transfer of the component to the molded article becomes small, and the releasability is ensured by the hydrocarbon-based wax on the low melting point side.

The difference between the melting points of the two types of hydrocarbon waxes is preferably 90 ℃ or less. The upper limit of the difference in melting point is preferably 80 ℃, 73 ℃, 63 ℃, 60 ℃ and 55 ℃ in this order. The lower limit of the difference in melting point is more preferably 30 ℃, 35 ℃, 40 ℃ in this order.

The amount of the hydrocarbon-based wax to be blended in the wax emulsion may be appropriately set depending on the type and blending ratio of the hydrocarbon-based wax, the type and blending amount of other blending components, and the like. For example, the total amount of the hydrocarbon-based wax is preferably 1 wt% or more and 30 wt% or less with respect to 100 wt% of the wax emulsion. In this case, emulsion particles can be easily formed, and the releasability of the molded article from the mold and the adhesion of the molded article are good. The lower limit of the total amount of the hydrocarbon-based wax is more preferably 3% by weight. The upper limit of the total amount of the hydrocarbon-based wax is more preferably 20% by weight, and still more preferably 15% by weight.

The release agent according to one embodiment of the present invention includes a wax emulsion obtained by emulsifying two types of hydrocarbon waxes having a difference in melting point of 25 ℃ or higher, and the weight ratio of the hydrocarbon wax on the high melting point side to the hydrocarbon wax on the low melting point side is 50/50 or more and 92/8 or less. In this case, it is considered that this is because the releasability of the molded article from the mold and the adhesion of the molded article are good. If the weight ratio is set to this value, the film strength of the release agent becomes high due to the hydrocarbon-based wax on the high melting point side, so that transfer on the molded article becomes small, and the releasability is secured due to the hydrocarbon-based wax on the low melting point side. The lower limit of the weight ratio is more preferably 53/47, and still more preferably 60/40. The upper limit of the weight ratio is more preferably 88/12, and still more preferably 82/18.

The wax emulsion comprises water. The water used may be any of tap water, industrial water, ion-exchanged water, distilled water, and the like, and may be either hard water or soft water. The amount of water to be added to the wax emulsion may be 70 wt% or more and 95 wt% or less with respect to 100 wt% of the wax emulsion. The lower limit of the amount of water is preferably 80% by weight, and the upper limit of the amount of water is preferably 90% by weight.

The wax emulsion is obtained by emulsifying a hydrocarbon wax with an emulsifier. As the emulsifier, a known surfactant can be suitably used.

As the surfactant, any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant can be used. The surfactant may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

Examples of the anionic surfactant include fatty acid salts and alkylsulfonic acid salts. Examples of the cationic surfactant include alkylamine salts and alkylammonium salts. Examples of the amphoteric surfactant include fatty acid type amphoteric surfactants, sulfonic acid type amphoteric surfactants, and the like. Examples of the nonionic surfactant include glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyalkylene alkyl ethers.

The amount of the emulsifier to be blended may be appropriately set depending on the kind of the emulsifier, the kinds of other blending components, the blending amount, and the like. For example, the amount of the emulsifier to be blended is preferably more than 0% by weight and 9.0% by weight or less based on 100% by weight of the wax emulsion. In this case, the desired emulsion particles can be easily formed, the stability of the wax emulsion is improved, and the molded article has excellent releasability. The lower limit of the amount of the emulsifier is more preferably 0.1% by weight, and still more preferably 0.5% by weight. The upper limit of the total amount of the emulsifier is preferably 7.0 wt%, 5.0 wt%, 3.0 wt% in this order.

Emulsification of the wax can be carried out by a conventional method, and a phase inversion emulsification method is preferably used from the viewpoint of stability at the time of emulsification.

In the case of preparing a wax emulsion, other additives such as an emulsification aid and a pH adjuster may be added.

Examples of the emulsification aid include higher alcohols such as cetyl alcohol and lauryl alcohol, higher fatty acids such as lauric acid, palmitic acid and stearic acid, oxidized wax, chlorinated paraffin, and liquid paraffin. The blending amount of the emulsification aid can be appropriately set depending on the kind of the emulsification aid, the kinds of other blending components, the blending amount, and the like. For example, the amount of the emulsification aid blended is preferably 0 wt% or more and 9.0 wt% or less with respect to 100 wt% of the wax emulsion. In this case, the target emulsion particles can be easily formed, the stability of the wax emulsion is improved, and the releasability between the molded article and the mold is excellent. The lower limit of the amount of the emulsification aid is more preferably 0.1% by weight, and still more preferably 0.5% by weight. The upper limit of the amount of the emulsification aid is more preferably 7.0% by weight, and still more preferably 5.0% by weight.

Examples of the pH adjuster include inorganic bases such as sodium hydroxide, potassium hydroxide, and ammonia, and organic bases such as triethylamine. The amount of the pH adjuster to be blended may be appropriately set depending on the type of the pH adjuster, the type of other blending components, the blending amount, and the like. For example, the amount of the pH adjuster is preferably 0 wt% to 3 wt% with respect to 100 wt% of the wax emulsion. In this case, the pH of the wax emulsion can be made weakly alkaline, so that corrosion of the mold can be prevented and the wax emulsion can be prevented from being deteriorated. The lower limit of the pH adjuster is more preferably 0.1% by weight, and still more preferably 0.2% by weight. The upper limit of the pH adjuster is more preferably 1 wt%.

The wax emulsion of the present embodiment can be used as it is as a mold release agent. The wax emulsion of the present embodiment may be further diluted with a diluent such as water to prepare a release agent as a stock solution. The dilution ratio can be appropriately set according to the amount of the hydrocarbon-based wax in the wax emulsion.

When the wax emulsion is diluted, the amount of the wax emulsion is preferably 1 wt% or more and 40 wt% or less with respect to 100 wt% of the release agent. The lower limit of the amount to be blended is more preferably 2% by weight, and still more preferably 5% by weight. The upper limit of the amount is more preferably 30% by weight, and still more preferably 20% by weight. The solid content is preferably 0.5 wt% or more and 2 wt% or less with respect to 100 wt% of the release agent.

When the release agent is prepared by diluting the wax emulsion, the wax emulsion and water are put into a vessel having a stirring device at an arbitrary ratio and stirred until a uniform solution is formed, whereby an aqueous release agent can be obtained. In the preparation, the substances which have already formed an emulsion are mixed with water without special heating.

As a method of applying the release agent of the present embodiment to a mold, there is a method of applying the release agent by spraying, brush coating, or the like. The amount of the non-volatile component of the release agent adhering to the mold per 1m²Is 0.5g to 20g, preferably 3g to 10 g. By applying the above amount to a mold, sufficient releasability can be obtained, mold fouling is reduced, and the method is economically advantageous.

The mold temperature at the time of molding using the mold release agent of the present embodiment is 40 ℃ to 80 ℃, preferably 60 ℃ to 80 ℃. If the mold temperature is too low, the evaporation rate of water as a solvent becomes slow, which is not preferable from the viewpoint of work efficiency.

The release agent of the present embodiment may contain, if necessary, an alcohol such as ethanol, a fluorine component, other release components such as a silicone component, and other components such as a rust inhibitor and a preservative.

Examples of the synthetic resin to be filled in the mold include a urethane resin, a polyethylene resin, a polypropylene resin, a polyester resin, an epoxy resin, and a phenol resin, and among them, a urethane resin is preferable.

Examples of the material to be adhered to the molded article include synthetic resins such as polyacrylic resins, polyamide resins, polyolefin resins, and polyvinyl chloride resins, natural leathers such as cattle, synthetic leathers, cloths, metals, and ceramics.

As the adhesive, various conventionally known adhesives can be used. Examples thereof include rubber adhesives such as styrene-butadiene rubber and chloroprene rubber, and thermosetting adhesives such as epoxy resin adhesives and urethane adhesives. The method for applying these adhesives is not particularly limited, and a method of applying them with a blade or brush, or a method of applying them with a spray may be used. Among these coating methods, a method of coating by spraying is preferable from the viewpoint of workability.

Examples

Hereinafter, examples of the present invention will be specifically described, but the present invention is not limited to these examples.

1. Preparation of the Release agent [ example 1]

Wax 1, wax 5, an emulsification aid, an emulsifier and a pH adjuster were heated and melted at the mixing ratios (expressed in parts by weight) shown in table 1 below, water (hot water) was slowly added, and phase inversion emulsification was performed to obtain a wax emulsion. The wax emulsion was diluted 9 times with water to obtain the mold release agent of example 1. The wax 5 is a mixture of two kinds of hydrocarbon waxes. With respect to the melting points of wax 1 and wax 5 in table 1, a mixture of wax 1 and wax 5 was subjected to DSC using a differential scanning calorimetry analyzer with a trade name of "esta 6000DSC 6200" (manufactured by Seiko Instruments), and the difference between 2 peaks was determined as the difference between the melting points of wax 1 and wax 5 from the peak tops of the obtained DSC curve. The melting points and melting point differences were determined in the same manner in other examples and comparative examples.

[ TABLE 1]

[ examples 2 and 3]

The mold release agents of examples 2 and 3 were prepared in the same manner as in example 1, except that the blending ratio of the wax 1 and the wax 5 was changed as shown in table 1.

[ examples 4 and 5]

The mold release agents of examples 4 and 5 were prepared in the same manner as in example 1 except that wax 3 and wax 5, and wax 1 and wax 6 were blended in the blending ratio shown in table 1.

[ comparative examples 1 to 7]

The mold release agents of comparative examples 1 to 7 were prepared in the same manner as in example 1 except that the wax was blended in the blending ratio shown in table 2 below.

[ TABLE 2 ]

2. Evaluation of Performance

Molded articles were produced as described below, and the releasability from the mold and the adhesiveness of the molded articles were evaluated.

[ production of molded article ]

13g of the release agents of examples 1 to 5 and comparative examples 1 to 7 were uniformly sprayed on the inner wall surface of the test mold heated to 65. + -.3 ℃ for each mold using a spray gun.

The polyurethane resin is injected into the mold and cured to obtain a molded article.

[ evaluation of mold releasability ]

After the polyurethane resin was cured, the load required to demold the molded article from the mold was measured by a push-pull dynamometer. The load was recorded as the release force. The evaluation of the mold release force is shown in the lower stages of tables 1 and 2. The evaluation is as follows.

A: less than 80N

B: 80N or more and less than 100N

C: over 100N

[ evaluation of adhesiveness ]

An adhesive was applied to both the molded article and the leather with bristles, the leather was attached to the molded article, left to stand in a thermostatic bath at 23 ℃ for 24 hours, and then the leather was peeled from the molded article by 180 ° peeling, and the load required for peeling was measured with a push-pull force meter. The load is recorded as the adhesion. The evaluation of the adhesion is shown in the lower stages of tables 1 and 2. The evaluation is as follows.

A: 15N or more

B: 10N or more and less than 15N

C: less than 10N

Fig. 1 is a graph in which the relationship between the melting point difference and the mold release force, and the relationship between the melting point difference and the adhesion force were obtained based on examples 3, 4, and comparative example 3 in which the weight ratio of the wax on the high melting point side to the wax on the low melting point side was the same. The abscissa of fig. 1 represents the melting point difference (c), the left ordinate represents the mold release force (N), and the right ordinate represents the adhesion force (N). In fig. 1, the solid line shows the relationship between the melting point difference and the mold release force, and the broken line shows the relationship between the melting point difference and the adhesion force.

From tables 1 and 2 and fig. 1, it is understood that in the case of the examples in which the difference in melting point between the two types of hydrocarbon waxes is 25 ℃ or more, the releasability of the molded article from the mold and the adhesion of the molded article are good as compared with the comparative examples.

The upper limit of the difference in melting point is preferably 90 ℃, 80 ℃, 73 ℃, 63 ℃, 60 ℃ and 55 ℃ in this order. The lower limit of the difference in melting point is more preferably 30 ℃, 35 ℃ and 40 ℃ in this order.

Fig. 2 is a graph showing the relationship between the mold release force and the ratio of the hydrocarbon-based wax on the high melting point side to 100 wt% of the total amount of the hydrocarbon-based wax, and the above ratio and the adhesion force, based on examples 1, 2, 3, and comparative example 1, which have the same difference in melting point. The horizontal axis of fig. 2 is a ratio (%), the left vertical axis is a mold release force (N), and the right vertical axis is a bonding force (N). In fig. 2, the solid line shows the relationship between the ratio and the mold release force, and the broken line shows the relationship between the ratio and the adhesion force.

From tables 1 and 2 and fig. 2, it is understood that in the case of examples in which the ratio of the hydrocarbon-based wax on the high melting point side is 50% by weight or more and 92% by weight or less, that is, in the case in which the weight ratio of the hydrocarbon-based wax on the high melting point side to the hydrocarbon-based wax on the low melting point side is 50/50 or more and 92/8 or less, the releasability and adhesiveness are better than those of comparative examples. The lower limit of the weight ratio is more preferably 53/47, and still more preferably 60/40. The upper limit of the weight ratio is more preferably 88/12, and still more preferably 82/18.

From the above, it was confirmed that the release agent of the present invention has good releasability between a molded article and a mold, and also has good adhesion of the molded article.

In the above embodiment, the case where the wax emulsion is prepared by mixing two types of hydrocarbon waxes has been described, but the present invention is not limited thereto, and for example, a wax emulsion may be prepared by mixing three types of hydrocarbon waxes.