Release agent, laminate and molded body using the same, and method for producing laminate and molded body

Abstract

To provide a mold-releasing agent having excellent mold releasability.SOLUTION: A mold-releasing agent includes an aqueous dispersion containing a silicone and a wax, and is separated into a layer involving the silicone as a main component and a layer involving the wax as a main component by evaporation removal of water from the aqueous dispersion.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a release agent, a laminate and a molded article using the same, and a method for producing the laminate and the molded article. [Background technology]

[0002] When molding synthetic resins such as polyester resins and polyurethane resins, it is common to apply a release agent to the mold in order to facilitate the release of the molded product from the mold. Known examples of such release agents include silicone-based and wax-based release agents (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5848909 Summary of the Invention [Problem to be solved by the invention]

[0004] Release agents that are solely made of silicone-based compounds have room for improvement in terms of initial releasability, and wax-based release agents have the problem that they are difficult to apply to molded articles that are molded at high temperatures because they carbonize when heated above a certain temperature.

[0005] A primary object of the present disclosure is to provide a release agent having excellent releasability. [Means for solving the problem]

[0006] As a result of intensive research, the present inventors have found that a release agent containing an aqueous dispersion containing silicone and wax, which separates into a layer mainly composed of silicone and a layer mainly composed of wax upon evaporation and removal of water from the aqueous dispersion, has excellent release properties, and have thus completed the present invention.

[0007] That is, the release agent according to one aspect of the present disclosure contains an aqueous dispersion containing silicone and wax, and is characterized in that, by evaporation and removal of water from the aqueous dispersion, the release agent separates into a layer mainly composed of silicone and a layer mainly composed of wax.

[0008] The above-mentioned release agent may be used in the production of a molded body using a mold, and the layer containing silicone as a main component may be adhered to the mold, and the layer containing wax as a main component may be adhered to the molded body.

[0009] In the above-mentioned release agent, the solid content ratio of the silicone to the wax may be 1.0 or more and 4.5 or less in terms of mass ratio (silicone / wax).

[0010] A method for producing a molded body according to one aspect of the present disclosure includes applying any one of the release agents described above to a mold, heating the mold to evaporate and remove water from the release agent, placing a raw material for a molded body in the mold, and removing the molded body from the hardened raw material for the molded body from the mold.

[0011] A molded article according to one embodiment of the present disclosure is a molded article coated with a layer mainly made of wax, and by peeling the silicone-based layer from a release film formed by laminating the wax-based layer and a silicone-based layer, only the wax-based layer is adhered.

[0012] A laminate according to one embodiment of the present disclosure is a laminate of a release film and a molded body produced in a mold, the release film having a layer mainly made of silicone formed on the side that is to be attached to the mold, and a layer mainly made of wax formed on the side that is to be attached to the molded body.

[0013] The method for producing a laminate according to one embodiment of the present disclosure is characterized by including production steps (1) to (4). (1) applying a release agent containing an aqueous dispersion of silicone and wax to a mold; (2) A process for laminating a release film separated into a layer mainly composed of silicone and a layer mainly composed of wax on the mold by heating the mold and evaporating and removing water from the release agent. (3) placing a raw material for a molded body on the mold having the release film; (4) A step of laminating a green body onto the release film by curing the green body raw material. Effect of the Invention

[0014] According to the present disclosure, a release agent having excellent releasability can be realized. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, embodiments of the present disclosure will be described in detail.

[0016] A release agent according to one aspect of the present disclosure is a release agent that contains an aqueous dispersion containing silicone and wax, and is characterized in that, by evaporation and removal of water from the aqueous dispersion, it separates into a layer containing the silicone as a main component and a layer containing the wax as a main component. The release agent according to one embodiment of the present disclosure has excellent heat resistance in addition to releasability. Excellent releasability means that the molded body has excellent releasability (peeling ability) from the mold. Excellent heat resistance means that even when used under high temperature conditions, the mold stain caused by carbonization of the release agent can be suppressed, and the agent can be suitably used for molding a molded body under high temperature conditions.

[0017] (Release agent) The release agent of the embodiment contains an aqueous dispersion containing silicone and wax. The aqueous dispersion containing silicone and wax contains silicone and wax.

[0018] As the silicone, for example, one having a polysiloxane as a main skeleton structure can be used. Examples of such silicone include dimethylpolysiloxane, modified polysiloxane, methylphenylpolysiloxane, etc. Modifications include, for example, epoxy modification, alkyl modification, amino modification, carboxyl modification, polyether modification, etc. As the silicone, alkyl-modified polysiloxane, amino-modified polysiloxane, dimethylpolysiloxane, etc. can be suitably used. One type of silicone may be used alone, or two or more types may be used in combination.

[0019] Examples of waxes include hydrocarbon waxes such as natural waxes and synthetic waxes. Examples of natural waxes include mineral waxes such as animal and vegetable waxes and petroleum waxes. Examples of petroleum waxes include paraffin wax, microcrystalline wax, and petrolatum. Examples of synthetic waxes include Fischer-Tropsch wax and polyethylene wax. Waxes may be used alone or in combination of two or more.

[0020] The melting point of the wax is preferably 40° C. or higher and 80° C. or lower, in which case the mold releasability and heat resistance are good.

[0021] When a release agent containing an aqueous dispersion of silicone and wax is applied to the inner surface of a mold and the mold is heated, the water in the aqueous dispersion evaporates and is separated into a layer mainly made of silicone and a layer mainly made of wax. When the release agent is applied to the inner surface of the mold with the inside of the mold (the part where the raw material for the molded body is placed) facing horizontally upward, a layer mainly made of silicone is formed on the mold side and a layer mainly made of wax is formed on the molded body side due to differences in melting temperature and specific gravity between the silicone and wax. The layer mainly made of wax has an adhesive function with the molded body.

[0022] In a release film formed by laminating a layer mainly made of silicone and a layer mainly made of wax, three types of failure occur: cohesive failure in the layer mainly made of silicone, interfacial failure at the interface between the layer mainly made of silicone and the layer mainly made of wax, and cohesive failure in the layer mainly made of wax, and thus outstanding releasability is exhibited.

[0023] In addition, the layer mainly made of silicone and the layer mainly made of wax adheres to the molded body by interfacial peeling, which can suppress adhesion of carbonized components to the mold. Therefore, even when used under high temperature conditions, mold contamination can be suppressed, and the number of steps required for cleaning mold contamination can be reduced, leading to cost reduction.

[0024] The types of silicone and wax contained in the aqueous dispersion can be appropriately selected depending on, for example, the melting temperature, specific gravity, polarity, and the like, of each of the silicone and wax.

[0025] The content of silicone in the aqueous dispersion containing silicone and wax in the release agent can be appropriately set according to the type of silicone, the type and content of other components, etc. For example, the content of silicone is preferably 2 parts by mass or more and 16 parts by mass or less when the entire release agent is 100 parts by mass. By setting the content of silicone within the above range, a release film with excellent releasability and heat resistance can be formed. The lower limit of the content of silicone is more preferably 8 parts by mass. The upper limit of the content of silicone is more preferably 11 parts by mass.

[0026] The wax content in the aqueous dispersion containing silicone and wax in the release agent can be appropriately set according to the type of wax, the type and content of other components, etc. For example, the wax content is preferably 2 parts by mass or more and 10 parts by mass or less when the entire release agent is 100 parts by mass. By setting the wax content within the above range, the adhesion between the wax component and the mold can be improved, and a release film with excellent releasability can be formed. In addition, the adhesion amount to the molded body is kept appropriate, and the secondary processability of the molded body is improved. The lower limit of the wax content is more preferably 4 parts by mass. The upper limit of the wax content is more preferably 6 parts by mass.

[0027] The content of silicone and wax is not particularly limited, but the mass ratio of solids (silicone / wax) is preferably 1.0 or more and 4.5 or less. In this case, the dispersion stability of the emulsion is improved, and the separation of the silicone component and the wax component is good, so that a release film with excellent releasability and heat resistance can be formed. The lower limit of the mass ratio is more preferably 1.3 or more, and even more preferably 1.5 or more. The upper limit of the mass ratio is more preferably 4.2 or less, even more preferably 3.0 or less, and most preferably 2.5 or less.

[0028] The aqueous dispersion containing silicone and wax contains water. The water used may be tap water, industrial water, ion-exchanged water, distilled water, or the like, and may be either hard water or soft water.

[0029] The aqueous dispersion containing silicone and wax is an emulsion obtained by emulsifying silicone and wax using a surfactant and dispersing them uniformly in water. The aqueous dispersion containing silicone and wax may be an emulsion obtained by mixing an aqueous dispersion containing silicone (silicone emulsion) and an aqueous dispersion containing wax (wax emulsion). The silicone emulsion is obtained by emulsifying silicone with a surfactant. The silicone emulsion may be obtained by emulsion polymerizing silicone dispersed in water using a surfactant with a polymerization initiator. The wax emulsion is obtained by emulsifying wax with a surfactant. The emulsion of silicone and wax and the emulsion polymerization of silicone can be carried out by known methods.

[0030] The surfactant used for emulsification may be any of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants. Examples of anionic surfactants include fatty acid salts and alkylsulfonate salts. Examples of cationic surfactants include alkylamine salts and alkylammonium salts. Examples of amphoteric surfactants include fatty acid amphoteric surfactants and sulfonic acid amphoteric surfactants. Examples of nonionic surfactants include glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxysorbitol fatty acid esters, and polyoxyalkylene alkyl ethers. The surfactant used for emulsion polymerization may be a reactive surfactant having a radical polymerizable functional group in the molecule. The surfactant may be used alone or in combination of two or more. The content of the surfactant may be appropriately set depending on the type of surfactant, the type and content of other components, and the like.

[0031] Examples of the polymerization initiator used in the emulsion polymerization include potassium persulfate and ammonium persulfate, which are used in normal radical polymerization.

[0032] The release agent of the embodiment contains water. Examples of water that can be used include tap water, industrial water, ion-exchanged water, distilled water, pure water, and ultrapure water, and may be soft or hard water. One or more of these waters may be mixed and used. The content of water in the release agent is not particularly limited, but is preferably 70 parts by mass or more and 96 parts by mass or less, and more preferably 80 parts by mass or more and 90 parts by mass or less, based on 100 parts by mass of the entire release agent.

[0033] In addition to the above-mentioned components, the release agent of the embodiment may contain various additives as necessary within the range that does not impair the effects of the present invention. Examples of additives include leveling agents. The amount of each additive may be appropriately selected according to the conventional technology.

[0034] The leveling agent may be, for example, a fluorine-based surfactant. Adding an appropriate amount of the leveling agent improves the applicability to the mold.

[0035] In addition to the above-mentioned components, the release agent of the embodiment may contain neutralizing agents (e.g., inorganic alkalis, etc.), alcohols, rust inhibitors, preservatives, etc. These additives may be added as necessary within the range that does not impair the effects of the present invention.

[0036] The release agent of the embodiment can be used as it is for producing a molded body. The release agent of the embodiment may be used as a stock solution, and then diluted with a diluent such as water to produce a release agent. When the release agent of the embodiment is diluted, the dilution ratio may be appropriately set according to the content of silicone and wax in the aqueous dispersion, etc.

[0037] The release agent of the embodiment can be obtained by mixing the above-mentioned components. By dispersing the silicone and wax in the form of fine particles in water, a release agent in which the silicone and wax, which are poorly compatible, are uniformly dispersed can be obtained.

[0038] (Laminate) The laminate of the embodiment includes a molded body and a release film containing the above-mentioned release agent.

[0039] Examples of the raw material of the molded body include rubber, thermoplastic resin, and thermosetting resin. Examples of the rubber include synthetic rubber such as natural rubber, isoprene, butadiene, and styrene butadiene. Examples of the thermoplastic resin include polyethylene resin and polypropylene resin. Examples of the thermosetting resin include polyurethane resin, epoxy resin, and phenolic resin. Examples of the raw material of the molded body include polyethylene resin, and more preferably polyethylene terephthalate (PET). The raw material of the molded body may be a mixture of the above-mentioned thermoplastic resin and fiber, or a mixture of the above-mentioned thermosetting resin and fiber. Examples of the fiber include carbon fiber and glass fiber. The raw material of the molded body may be liquid or solid.

[0040] The release film is formed by applying the release agent to the inner surface of a mold, heating the mold, and evaporating and removing water from the release agent. The release film has a layer mainly made of silicone formed on the side that is attached to the mold, and a layer mainly made of wax formed on the side that is attached to the molded body. The thickness of the release film is not particularly limited, but is preferably 0.1 μm or more and 100 μm or less.

[0041] (Molded body) The molded article of the embodiment is coated with a layer of the release film mainly made of wax. The layer mainly made of wax is obtained by peeling off the layer mainly made of silicone from a release film formed by laminating a layer mainly made of wax and a layer mainly made of silicone.

[0042] The molded body is obtained by removing the laminate produced in the mold from the mold. Before being removed from the mold, the molded body is adhered to the release film due to the adhesive function of the wax-based layer formed on the molded body side. When being removed from the mold, the silicone-based layer of the release film adhered to the molded body is peeled off due to the interface destruction between the wax-based layer and the silicone-based layer of the release film, and only the wax-based layer adheres to the molded body.

[0043] (Method of manufacturing laminate) The method for producing a laminate according to the embodiment includes the steps of: (1) applying a release agent containing an aqueous dispersion of silicone and wax to a mold; (2) A process of laminating a release film separated into a layer mainly made of silicone and a layer mainly made of wax on the mold by heating the mold and evaporating and removing water from the release agent; (3) placing a raw material for a molded body in a mold having a release film; (4) A step of laminating a molded body on the release film by hardening the molded body raw material. Includes.

[0044] The method of applying the release agent to the mold is by spray coating or brush coating. The amount of non-volatile components of the release agent adhering to the mold is 1 m 2 The preferred amount is 0.1 g to 50 g per unit. By applying the above amount to the mold, sufficient releasability is obtained, mold contamination is reduced, and the cost is excellent. Since the silicone and wax in the mold release agent are uniformly dispersed in water, it can be uniformly applied to the mold by a normal application method.

[0045] The mold temperature when laminating the release film may be a temperature sufficient to evaporate and remove the water in the release agent. The mold temperature is, for example, 60° C. or higher and 250° C. or lower, preferably 130° C. or higher and 220° C. or lower. In this case, the evaporation can be suitably promoted, and the denaturation of the release film to be formed can be suppressed.

[0046] The method for placing the molding raw material in the mold is not limited, but can be a known method depending on the properties and type of the molding raw material, such as placing a solid resin raw material in the mold or filling the mold by injecting a liquid raw material.

[0047] The molding raw material is cured by heat curing. Specifically, the molding raw material is cured by heating in opposing dies. This results in a laminate of the release film and the molded body obtained by curing the molding raw material.

[0048] The mold temperature when the molded body raw material is cured, in other words, the use temperature of the mold release agent, can be appropriately set depending on the molded body raw material to be cured, and can be, for example, from 60° C. to 250° C., preferably from 130° C. to 220° C. In this case, the molded body raw material can be appropriately cured, and the effects of the present invention can be fully exhibited.

[0049] The curing time for curing the raw material for the molded body may be set to a time that provides a sufficient degree of curing for the resulting cured molded body.

[0050] (Method of Manufacturing Molded Product) The manufacturing method of the molded body according to the embodiment includes the steps of applying a release agent to a mold, heating the mold to evaporate and remove water from the release agent, placing a raw material for the molded body in the mold, and removing the molded body from the mold in which the raw material for the molded body has hardened.

[0051] Among the steps included in the method for producing a molded body, the steps of applying a release agent to a mold, heating the mold to evaporate and remove water from the release agent, and placing a raw material for the molded body in the mold are the same as those in the method for producing the laminate described above.

[0052] After the laminate is manufactured, the mold is opened and the molded body in which the raw material for the molded body is hardened is taken out, thereby obtaining a molded body. When the molded body is taken out, the layer mainly made of silicone is peeled off from the release film made of the layer mainly made of wax and the layer mainly made of silicone adhered to the molded body. The peeled layer mainly made of silicone remains in the mold. In this way, a molded body coated with the layer mainly made of wax is obtained. EXAMPLES

[0053] Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.

[0054] 1. Preparation of Release Agent [Examples 1 to 9 and Comparative Examples 1 to 4] The components shown in Tables 1 and 2 below were weighed out so as to obtain the compositions (in parts by mass) shown in the tables, and mixed in a stirrer until uniform, to obtain release agents of Examples 1 to 9 and Comparative Examples 1 to 4. All of the components shown in Tables 1 and 2 below were commercially available products. The blending ratio (mass ratio) of the solid contents of silicone and wax, and the water content are shown in Tables 1 and 2. The water content means the total content of water contained in the release agent, and includes the water in the silicone emulsion and the wax emulsion.

[0055] Details of each component shown in Tables 1 and 2 are as follows. Silicone emulsion 1: Amino-modified polysiloxane, solid content 30 parts by weight Silicone emulsion 2: Alkyl-modified polysiloxane, solid content 54 parts by mass Silicone emulsion 3: Dimethylpolysiloxane, solid content 33 parts by mass Silicone emulsion 4: Dimethylpolysiloxane, solid content 37 parts by mass Silicone emulsion 5: Dimethylpolysiloxane, solid content 32 parts by weight Silicone emulsion 6: Dimethylpolysiloxane, solid content 34 parts by mass Silicone emulsion 7: Dimethylpolysiloxane, solid content 39 parts by weight Silicone emulsion 8: Amino-modified polysiloxane, solid content 30 parts by mass Wax emulsion 1: Base oil melting point 66°C, solid content 12.5 parts by mass Wax emulsion 2: Base oil melting point 66°C, solid content 25 parts by mass Wax emulsion 3: Base oil melting point 88°C, solid content 16 parts by mass Fluorosurfactants 1: Anionic Fluorosurfactants 2: Anionic

[0056] 2.Performance evaluation The prepared release agents were evaluated for their layer separation properties. Molded articles were produced as follows, and the mold releasability of the molded articles from the mold and the mold contamination (mold staining) were evaluated.

[0057] [Evaluation of stratification] 5 g of the release agent was weighed out into a petri dish and heated at 120°C for 1 hour using an open heating device (such as a hot plate). The release agent in the petri dish was then transferred to a glass container and left to stand for 1 hour in a thermostatic chamber at 80°C. The appearance after standing was checked to visually evaluate the layer separation of the release agent. The evaluation of layer separation is shown in the lower part of Tables 1 and 2. The evaluation details are as follows. ○: Layer separation has occurred ×: No layer separation occurs, and the mixture is in a mixed state. [Production of Molded Products] The obtained release agent was sprayed uniformly onto the inner surface of a test mold (made of SUS, molded product size: 100 mm wide x 100 mm long x 3 mm high) using a spray gun, at about 0.1 g per mold. The water in the release agent was evaporated and removed by heating at 200°C for 2 minutes, and a release film was laminated onto the mold. Unstretched PET (weight per unit area: 2000 g / m 2 ) was placed in the mold. The PET was cured by applying heat and pressure at a pressure of 0.4 MPa in a press machine heated to 160°C. It was then gradually cooled at room temperature to obtain a molded product.

[0058] [Evaluation of initial releasability] After the PET hardened, the load required to remove the hardened PET from the mold was measured using a push-pull scale. This load was taken as the initial demolding force. The evaluation of the initial demolding force is shown in the lower part of Tables 1 and 2. The evaluation details are as follows: ◎: Less than 0.7N ○: 0.7N or more but less than 1.1N ×: 1.1N or more

[0059] [Evaluation of continuous releasability] After the initial demolding, the same molding was carried out five times in succession without applying new release agent, and the load required to demold the hardened PET from the mold each time was measured using a push-pull scale. The average of the loads obtained was taken as the continuous demolding force. The evaluation of the continuous demolding force is shown in the lower part of Tables 1 and 2. The evaluation details are as follows: ○: Less than 0.6N ×: 0.6N or more

[0060] [Evaluation of contamination] A metal plate was placed on a part of the mold (a part not used for molding) to form an area where the release agent was not applied. Using this mold, molding was carried out in the same manner as in the evaluation test of continuous mold releasability described above. The mold was then left to stand in a press for one hour, and the metal plate was removed. After leaving the mold to stand, the appearance of the areas on the mold where the release agent was applied and the areas on the mold where it was not applied was checked, and the state of contamination of the mold due to the adhesion of carbonized materials was visually evaluated. The evaluation of contamination is shown in the lower part of Tables 1 and 2. The evaluation details are as follows: ○: Little change in appearance, good mold contamination resistance ×: Partial discoloration and mold contamination observed

[0061] [Table 1]

[0062] [Table 2]

[0063] As is clear from Tables 1 and 2, the release agents of the examples, which contain an aqueous dispersion containing silicone and wax and are separated into a layer mainly composed of silicone and a layer mainly composed of wax by evaporation and removal of water in the aqueous dispersion, had superior release properties compared to the comparative examples. The release agents of the examples were excellent not only in initial release properties, which is the first time, but also in continuous release properties over multiple applications after the first time. Therefore, the number of applications of the release agent can be reduced, leading to improved production efficiency and cost reduction. In addition, the release agents of the examples had excellent mold contamination resistance even when used under high temperature conditions such as 160 ° C. It was confirmed that the deposition of carbonized materials on the mold was well suppressed, the agent could be used suitably under high temperature conditions, and had excellent heat resistance.

[0064] In the case of the examples in which the mass ratio of the solid content of silicone to wax (silicone / wax) is 1.0 or more and 4.5 or less, the releasability is superior to that of the comparative examples. The lower limit of the mass ratio is more preferably 1.3 or more, and even more preferably 1.5 or more. The upper limit of the mass ratio is more preferably 4.2 or less, even more preferably 3.0 or less, and most preferably 2.5 or less.

[0065] From the above, it was confirmed that the release agent of the present disclosure has excellent release properties.

[0066] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all modifications within the scope of the claims and the scope equivalent to the claims.

Claims

1. Contains an aqueous dispersion containing silicone and wax, The water in the aqueous dispersion is evaporated and removed, whereby the aqueous dispersion is separated into a layer mainly composed of the silicone and a layer mainly composed of the wax, The release agent has a solid content ratio of the silicone to the wax, expressed as a mass ratio (silicone / wax) of 1.0 or more and 4.5 or less.

2. Used to manufacture molded products using a mold, The silicone-based layer is attached to the mold. The layer containing the wax as a main component is applied to the molded body. The release agent according to claim 1 , which is applied to each of the surfaces.

3. A release agent as described in claim 1 or claim 2, wherein the solid content ratio of the silicone to the wax is 1.3 or more and 4.2 or less in mass ratio (silicone / wax).

4. The release agent according to claim 1, further comprising at least one selected from the group consisting of surfactants, polymerization initiators, leveling agents, neutralizing agents, alcohols, rust inhibitors, and preservatives.

5. Coating a mold release agent according to any one of claims 1 to 4 onto a mold, Heating the mold to evaporate and remove water from the release agent; A raw material for a compact is placed in the mold, The molded body obtained by hardening the molded body raw material is removed from the mold. A method for producing a molded body.

6. A laminate of a release film and a molded body produced in a mold, A laminate, characterized in that the release film has a layer mainly made of silicone formed on the side that is attached to the mold, and a layer mainly made of wax formed on the side that is attached to the molded body.

7. A method for producing a laminate, comprising the steps of (1) to (4): (1) applying a release agent containing an aqueous dispersion of silicone and wax to a mold; (2) A process of heating the mold to evaporate and remove water from the mold release agent, thereby laminating a mold release film separated into a layer mainly composed of silicone and a layer mainly composed of wax on the mold; (3) placing a molded body raw material on the mold having the release film; (4) A step of laminating a molded body on the release film by curing the molded body raw material.

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