JPS581516A - Method for releasing silicone molded article from mold - Google Patents

Abstract

PURPOSE:To release a silicone molded article smoothly and easily, by using a specific cellulose acetate type material with a high acetylation degree as a mold releasing layer of a mold releasing material. CONSTITUTION:Cellulose acetate with an acetylation degree of 54-62.5% (that is, di- or triacetate, pref., triacetate) 1 is laminated to a base material 2, for example, through an adhesive 3 to form a mold releasing material and, by using this mold releasing material, silicone such as polyorganosiloxane or the like is molded and the resulting molded article is released from a mold without deforming and damaging the same. In this case, when the base material 2 is a porous substance such as paper or the like a barrier layer 4 is preliminarily provided on the base material to prevent penetration of an acetate solution 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for smoothly and easily releasing a silicone molded product during production.

In general, the silicone raw materials used to manufacture various molded silicone sheets are either one-component or two-component, and for curing, either room temperature curing or heat curing is often used. There is.

When attempting to sufficiently adhere silicone such as these to various adherends, it is generally difficult to adhere silicone to the adherend, so it is often necessary to treat the adherend with a silane coupling agent or the like in advance. There are many.

However, although it may be difficult to bond, silicone adheres to the adherend to the extent that it exhibits a certain degree of peeling resistance. If the silicone molded product is not released from the mold after being released from the mold, the silicone molded product will often release from the mold and become thin.Especially when the modicolas of the silicone molded product is low or the silicone molded product In the case of a thin sheet, if the mold releasability is not sufficient, the silicone molded product will be forcibly peeled off during release, which may deform or damage the silicone molded product.

In the present invention, a silicone raw material for molding is placed in a mold release mold, for example, in a mold release mold, and after curing, a molded product such as a silicone sheet is produced by a predetermined process such as curing. It can be peeled off from the mold release type without any problems such as peeling.
This technology is based on the discovery of a former mold system that can be released to obtain molded products such as silicone sheets.

For example, a case will be described in which the release month is for the previous mold sheet. In general, there are many products that have been subjected to mold release treatment, such as paper, nonwoven fabric, plastic film, metal foil, etc., which are subject to a release process. These front mold sheets d polydimethyl siloxane as a mold release agent and polymethyl high F.
The film is formed by curing and reacting rhodiene siloxane with a crosslinking agent and a tin-based or platinum-based material η as a contact, and has a mold release silicone as a mold release layer.

However, when trying to mold and release a silicone sheet using such release note soil, the general pre-form sheet as described above is used to coat the soil with a silicone raw material for molding, dry it, and turn it into RSP to form a silicone sheet. Even if a sheet is formed, the silicone sheet will not be the same as the material 11 of the previous mold sheet.
Since the mold is also made of silicone, the formed silicone sheet adheres closely to the release sheet, making it impossible to release or peel it off, making it impossible to obtain the desired silicone sheet.

In other words, the mold release agent is silicone, and the notebook to be molded on the second one is also silicone, so the silicone sticks together and forms an adhesive or almost adhesive state, which makes it difficult to remove. It ended up being impossible.

In addition, polyethylene, polypropylene, aminoalkyd resin, polyvinyl alcohol, etc. have traditionally been used as a release agent in mold release sheets, such as polyethylene, polypropylene, amino alkyd resin, polyvinyl alcohol, etc. At present, when used as a mold release agent, these mold release agents have no mold release or peelability at all, and cannot be used for molding silicone sheets, which is extremely inconvenient.

The inventors of the present invention have conducted extensive and thorough research on mold release agents that are suitable for molding molded products such as silicone sheets, not just conventional mold release agents. We discovered that cellulose acetate (hereinafter abbreviated as acetate) retains excellent effects as a mold release agent, and succeeded in producing a mold release material using this mold release agent. In other words, acetate has much better moldability than any of the various mold release agents mentioned above. When a molded product such as a silicone sheet is formed by coating and curing with heat etc., the molded product such as a silicone sheet can be easily peeled off from the release sheet, but there are many problems with various types of silicone sheets. It has been found that molded products can be easily manufactured.

The degree of acetylation of acetate used as a mold release agent in the present invention must be within the range of 54 to 62.5%,
In other words, it is diacetate. The higher the degree of acetylation, the better the releasability of silicone molded products tends to be, as shown in the examples of the present invention, and the higher the degree of acetylation, the better for achieving the object of the present invention. If the degree of acetylation is less than 54%, the mold releasability will be poor as shown in the comparative example, so it is not preferable, and if the degree of acetylation is 62.5%, all the hydroxyl groups that can be substituted by the acetyl groups in the acetate are acetylated. Theoretically, a degree of acetylation greater than this value cannot exist. In general, those with diacetate level 1 and 7) have a degree of acetylation of approximately 55%, and those with a degree of acetylation of approximately 61.5%. Without departing from the spirit of the present invention, any hydroxyl group other than the hydroxyl group substituted with J: or any acyl group such as propyl, butyryl, etc. may be substituted on the acer group. Plasticizers, known in acedate, unless beyond the scope
Refueling agent 1st oxidizing agent.

Nine color agent, face and a half-1. It is possible to use a mixture of antistatic agents and various resins.

In the present invention, (in the case of sheet-like products) non-woven fabrics, stretched or non-stretched plastic films, plastic films with metals etc.
The famous Sogetsu metal foils and other bonded materials are used. If profiteering chooses a material that can be embossed, has deep grains, or has a pattern, silicone can be used for sheet-like products. You can also make one. Furthermore, a halo such as the mold shown in FIG. 7 can be used, and the surface of this mold can be treated with a split mold with acetate. In this case as well, it is possible to make a molded article in the shape of 1.

Next, we will explain the main issue using diagrams.

Figures 1, 2, 6, and 4 show several examples of cross-sectional configuration diagrams of representative examples of the front molds used in the present invention. .

Figure 1 shows the use of the 4 types of film A + Boot 1 Pewter as the front mold sheet, and since the release agent is used as a release agent, both sides have a mold release effect. Figure 2 (,・
``Meat 1■Film-like acetate 1 to serve as a molding agent and base 1.''
2 and 2 are bonded together via adhesive 3, and a release sheet is formed with a 7° angle. Figure 6 does not show the pre-form sheet made by coating the soil of No. 2 with acetate 1, which is a mold release agent. , the soil is coated with acetate 1 as a mold release agent].

Figures 5 and 6 show typical examples of release sheets that have release sheets on both sides of the sheet.

FIG. 5 shows an example of a release sheet having a release agent layer and a barrier coating layer 4 on both sides of the structure shown in FIG.

FIG. 6 is an example of a double-sided release sheet that has the structure shown in FIG. 4 on one side of the base material 2 and the structure shown in FIG. 6 on the other side and has release properties on both sides.

In addition, although not shown in the figure, there is a double-sided release sheet that has the configurations shown in Figures 2 and 6 on both sides of Profit 2, and a double-sided release sheet that has the configurations shown in Figures 2 and 6 on each side of @2. Various configurations according to the present invention are possible, such as a double-sided release sheet having the configuration shown in FIGS. 2 and 4 on both sides of the base material 2. Furthermore, as shown in FIG. 7, it is also possible to use a release material that is not in the form of a sheet.

The adhesive 6 as shown in FIG. 2 of the present invention is not particularly limited as long as it can bond and bond the base material 2 and the film-like acetate 1, which is a release agent. One side of the film-like acetate 1 may be partially dissolved or swollen using a solvent capable of dissolving or swelling the film-like acetate 1, and the film-like acetate 1 may be bonded to the base material by drying and bonding.

In the present invention, as shown in FIG. 4, the release sheet may be provided with a single barrier layer. For example, if the base material 2 is a porous material such as paper, when trying to apply an acetate solution as a mold release agent to the soil, acetate will be applied to the surface of the material 2 because the base material 2 is porous. Not only that, but it may also penetrate into the inside of the base material 2, making it impossible to form a sufficient release layer on the surface of the base material 2. In these various cases, by providing a barrier layer on the base material 2 in advance and then applying a mold release agent thereon, the mold release layer can be uniformly and uniformly disposed on the surface. convenient.

For example, as shown in Embodiment B, one example is to provide a barrier layer 4 of low-strength polyethylene on paper.

In this way, when a single barrier layer 4 is provided as shown in FIG. 4, it may be coated with various resins in addition to polyethylene.
It is possible to use various types of barrier-coated materials, such as those coated with pigments, those coated with metal as foil, and those coated with vapor deposition. By providing the barrier layer 4, the coating amount of the mold release agent layer can be reduced, and it can also be used to control the gloss and smoothness of the surface of the mold release agent layer. I can do it.

Next, the silicone to be molded will be described.

The silicone that is specifically combined with acetate in the present invention is generally in the form of a liquid, paste, or viscous material similar to rubber, and after undergoing a crosslinking and curing reaction such as oxidation and quenching, it is shaped into a predetermined shape and made into a silicone molded product. Become.

Many silicones are mainly composed of polyorganosiloxanes in which the main substituents of the siloxane are methyl groups. In addition to the methyl group, halide alkyl groups, mercapto groups, α-methylstyrene groups, α-olefin groups, chlorophenyl groups, cyanethyl groups, carboxylic acid groups, hydroxyl groups, etc. may be partially introduced as substituents.

The terminal groups of polyorganosiloxanes are often terminated with organic groups, but may also be terminated with hydrolyzable groups such as hydroxyl groups, alkoxyl groups, and chloro groups.

Various reactions are involved in the crosslinking reaction. For example, in the case of a crosslinking reaction, a part of the polyorganosiloxane is substituted with a vinyl group, and this is an active reaction such as polymethylhydrodiene polysiloxane. A crosslinking reaction may be carried out by an addition reaction in the presence of a catalyst between a polyorganosiloxane having a hydrogen group and a group II metal compound such as platinum. Examples of condensation reactions include parts of polyorganosiloxane whose end groups are substituted with hydroxyl groups, alkoxyl groups, chlorine groups, etc., and where active hydrogen groups such as polymethylhydrogensiloxane are substituted. In some cases, the polyorganosiloxane and the polyorganosiloxane are subjected to a condensation reaction in the presence of a tin-based, zinc-based, or amine-based catalyst to cause a crosslinking reaction. In some cases, the terminal groups of organosiloxane are acetyl groups, ethoxyl groups, etc., and the terminal groups undergo condensation reactions such as acetic acid removal and ethanol removal in the presence of water and a tin or zinc catalyst. In addition, there are cases where the crosslinking reaction is carried out using peroxide, and cases where the crosslinking reaction is carried out using radiation such as electron beams and ultraviolet birch.

In any case, after the crosslinking reaction, these silicones hardly have a tackiness like that of adhesives. The silicone used in the present invention includes various pigments.

Colorants 1 Fillers and additives such as blowing agents, flame retardants, antistatic agents, conductive agents, etc. may also be added. There are also those containing solvents such as toluene, hexane, trichlene, ff[ethyl, etc., and those without solvents.

Further, it is not preferable to mix and use a silane coupling agent since this may impair the releasability of the release sheet.

Furthermore, when it is made into a silicone sheet after crosslinking reaction.

On top of that is 1 cloth paper, non-woven fabric, and plastic film.

Sometimes metal foil or the like is attached and then peeled off from a release sheet using acetate as a release agent. Further, after the crosslinking reaction, a silicone sheet may be formed and then a silicone coating may be applied.

As described above, the feature of the present invention is that silicone and acetate used as a mold release agent are combined in a specific manner4, making it easy to form silicone molded products on a mold release sheet using acetate as a mold release agent. The point is that it can be peeled off from the release sheet. That is, after coating the silicone raw material on a mold release sheet using acetate as a mold release agent and causing a crosslinking reaction by heating or other means, the silicone molded product can be easily released from the mold release sheet without any problems. It is characterized by being able to be peeled off.

Next, a method for measuring the degree of acetylation will be described.

Approximately 1.0 g of the sample was dried at 100 to 105°C for 2 hours, then accurately weighed and transferred to a 300 ml Erlenmeyer flask with a stopper.

Next, add 40ml of 75% neutral alcohol and add 55ml of 75% neutral alcohol.
Immerse in a constant temperature water bath at ℃ for 60 minutes. After that, 0.5N
-Add 40rnt of NaOH solution and immerse for 15 minutes in a constant temperature water bath at 5℃, then seal the tank and heat at 25↓5℃ for 40 minutes.
Let stand for ~48 hours. Next, phenolphthalein is titrated with 0.5N-HaL as an indicator and added in excess of 5 ml.

Further, back titration is performed with a 0.5N NaOH solution, and the point at which a pale pink color appears is taken as the end point, and the degree of acetylation is calculated using the following formula.

A blank test was also conducted at the same time.

Drum a: Factor A of 0.5N-NaOH solution: Titration amount (m
t) Titration amount (mt) of 0,5N-NaOH solution required for A' blank b: 0.5N-H (!t factor B: Titration amount (ml) of 0,5N-HcA used in the sample)B 'Titer amount of 0,5 N-Hc L required for nitrogen blank (
mt) Next, the sample preparation methods of Examples and Comparative Examples will be described in more detail, but it should be noted that the present invention is not limited in any way by the Examples, beyond the gist thereof. Of course.

Example 1 A release sheet made of acetate film (product name: Fujitac, thickness 50 μm, manufactured by Fuji Film KK) with an acetylation degree of about 61.5%.

Example 2 The film of Example 1 was prepared using low-density polyethylene extruded by hot melt extrusion as an adhesive, and the basis weight was 80 g/2.
A release sheet laminated with high-quality paper.

Example 3 Acetate with a degree of acetylation of approximately 61.5% (trade name: LACLT)
35 manufactured by Daicel KK) in a mixture of methylene chloride and ethanol at a weight ratio of 9:1 to make a 5% solution.
/-2 A release sheet made of polyethylene (thickness 20μ) coated with 6 x 2 (solid content) and dried.

Example 4 A release sheet obtained by applying the 5% solution in Example 6 to a 68μ polyester film at 2g/m2 (solid content) and drying it.

Example 5 Acetate with a degree of acetylation of about 55% (trade name: LAC, L-2
(manufactured by Daicel KK) in acetone to make a 5% solution.
Release sheet coated with Sea 2 (solid content) and dried.

Comparative example 1 Low density polyethylene (trade name, LK30. Mitsubishi Yuka KK
A coated sheet made by extruding and coating 25μ thick unbleached kraft paper with a basis weight of 75g/m2.

Comparative Example 2 Polypropylene for extrusion coating (trade name, Sho Aroma)
LR-510, manufactured by Showa Denko KK) with a basis weight of 16 og/m2
A coated sheet extruded to a thickness of 30μ on high-quality paper.

Comparative Example 6 Amino alkyd resin (trade name, Toxinol TGLV:
Tesmin TMFU=5:5 mixture, Tokushima essential oil KK
A 5% solution was obtained by diluting the curing catalyst (manufactured by Paratoluene Sulfone) with co-nitoluene, and coating the solution at 3 g/rn2 (solid content) on glassine paper with a basis weight of 70 g/rn2, and drying and curing it. sheet.

Comparative Example 4 Addition-reactive silicone for release paper (trade name: Shin-Etsu Silicone KS 772, manufactured by Shin-Etsu Chemical KK) was diluted with toluene together with a catalyst to make a 4% solution, and 1 g/n12 (solid) was prepared on polyethylene extrusion coated paper. Min.) Coated sheet that has been dried and cured.

Comparative Example 5 A catalyst was mixed with solvent-free addition reaction silicone for release paper (trade name: Shin-Etsu Silicone KNS 204, manufactured by Shin-Etsu Chemical KK), and the mixture was coated with 29-2 (solid content) on polyethylene extrusion coated paper. Cured coating sheet.

Comparative Example 6 A coated sheet obtained by applying 6 g/rn2 of a 5% aqueous solution of polyvinyl alcohol (trade name, Hohar 117, manufactured by Kuraray KK) to a high-quality paper with a basis weight of 160 g/rn2 and drying it.

Comparative Example 7 Polyester film (Lumirror film, thickness 68μ
, made by Toshi KK).

Comparative Example 8 Acetate with a degree of acetylation of approximately 48% (trade name: LACLLIO
(manufactured by Daicel KK) in acetone to make a 5% solution, and this was applied to glassine paper with a basis weight of 70 g/m2 at 6 g/r.
A coated sheet coated with n2 (solid content) and dried.

The following five formulations of silicone raw materials for molding were applied to Examples and Comparative Examples L-L2 and dried, and their releasability was measured.

L:)j 1 +Nl, Shinetsu/
Ricoh/Product name, lgE 1800 A 100〃B
10 Toluene 90 prescription 2 Shin-Etsu Silicone product name, ■GuE 1800, A
100rr B 2.5 Toluene 97.5 Formula 6 Part 1 - Resilicone brand name, SE 6706 A
50 tray silicone product name, SE 6706 B
50)・Ruen 100K
In E 1800 A, the main substituent is a methyl group, the main component is polyorganosoroxane having a vinyl group in part, and it also contains a platinum catalyst, and KE 1
800B is mainly composed of polyorganosiloxane having active hydrogen groups.

In addition, among SE 6706 A-B, one of the substituents is mainly a methyl group, and the main component is a mixture of a polyorganosiloxane partially containing a vinyl group and a polyorganosiloxane attached with an active hydrogen group. The other type is mainly composed of a mixture of a polyorganosilochylline whose substituent is mainly a methyl group and partially has a vinyl group, and a platinum-based catalyst.

Next, the measurement method will be described.

The silicone raw material of Formulation 1 was applied to the release-treated surface of the sheet of Example using an applicator with a clearance of 250μ, and dried and cured at 150°C for 10 minutes.
A silicone sheet is formed on the release sheet surface.

Next, this material was cut into pieces 25 mm wide and 20 cm long, and the silicone sheet was peeled off under the conditions shown below.
Measure peel strength. The measurement conditions were to peel the silicone sheet from the release sheet at an angle of 180°C using a universal tensile tester at a peeling rate of 500mm/6 at 20±2°C, and the peel strength at that time was expressed as V257. To prepare the measurement sample, in order to reinforce the silicone sheet, before cutting, it was lined with a film adhesive tape whose adhesive was the same as a silicone adhesive, and then the sample was cut and used for measurement.

Prescriptions 2 and B were also measured in the same manner as Prescription 1.

The comparative example was also measured in the same manner as the example.

Table 1.2.3 shows the release sheet of the example used in the test, the release treatment agent used for the release tart, and the peel strength with the release sheet in silicone raw material formulations 1, 2, and 6. . At the same time, the results of comparative examples are also shown.

As shown in Table 1.2.3, Examples 1 to 5 had a higher degree of peeling than Comparative Examples 1 to 8. It showed extremely low strength and very light peeling. Therefore, in this test method, the peel strength is 150 g/25 m.
If the peel strength is within □, the silicone molded sheet will not stretch, deform, or tear when peeled off, but the peel strength of all Examples 1 to 5 is 150.
It is far below g/25 m□. On the other hand, Comparative Example 1 is in a state where it cannot be separated. It can be seen that the peeling against the silicone sheet is significantly lighter only in the case of acetate with a degree of acetylation of 54% or more.

In Table 1.2.3, "unremovable" refers to cases in which the silicone sheet adheres to the release sheet and is impossible to remove, and also refers to cases in which the silicone sheet is torn and measurement is impossible even if it is forcibly removed. Refers to the state.

Regarding the mold release sheet of Example 1 used for carrying out the method of the present invention, a silicone sheet was made under the above-mentioned conditions using silicone raw material formulation 1 for molding, this silicone sheet was peeled off, and then the silicone sheet was again prepared using the raw material of formulation 1. The process of manufacturing silicone sheets under the same conditions on the same front mold sheet surface was repeated. This process was repeated 5 times, and the peel strength was 55.
It was also confirmed that the peel strength was within the range of ~65 g/25□4, and that even if the release sheet was used repeatedly, there was almost no change in peel strength, and that repeated use was possible.

[Brief explanation of the drawing]

The drawings are sectional views explanatory of several examples of mold release materials used in carrying out the present invention. When the acetate film used as a release agent and the base material are pasted together with an adhesive, Figure 6 shows the base material.When the acetate film used as the release agent is coated on the base material, Figure 4 shows the case where a barrier film is applied on the base material in advance. Figure 5 shows a case where both sides have a mold release agent layer and a barrier coating layer with the structure shown in Figure 4. The figure shows a case where the base material has the structure shown in FIG. 4 on one side and the structure shown in FIG. 6 on the other side and has releasability on both sides, and FIG. 7 shows the case of a non-sheet-shaped product. In the figure, 1: Acetate 2: Base material 6; Adhesive 4: Barrier layer Patent applicant Sanyo Kokusaku Pulp Co., Ltd. Agent Patent attorney Tadao Noma Patent attorney Tadayuki Noma Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Amendment to figure procedure August 28, 1980 Director General of the Japan Patent Office Shima 1) Haruki Tono1, Patent Application No. 1982-982152, Title of Invention: Method for releasing silicone molded products 6° Amendment Relationship with the patent applicant's case Patent applicant address 1-4-5 Marunouchi, Chiyoda-ku, Tokyo Name (
234) Sanyo Kokusaku Pulp Co., Ltd. President Ninomiya
Masayoshi 4, Agent 100 Address 23 Eiraku Building, 1-4-5 Marunouchi, Chiyoda-ku, Tokyo
Room 4 Telephone number: 214-2861 (Main) 6 Subject of amendment Column Z for detailed explanation of the invention in the Meikokusho Contents of amendment The following points in the detailed description of the invention will be amended. (1) On page 7, line 5, "propionyl" is corrected to "propionyl." (2) On page 18, line 11, the statement [Coating 3 #/m2] is corrected to "Coating 159/m2 (solid content)."

Claims (1)

[Claims] 1. When molding a silicone molded product without contacting it with a mold release material, the mold release layer of the mold release material has an acetylation degree of 54 to 54.
A method for releasing a silicone molded product, characterized by using a material whose main component is cellulose acetate within the range of 62.5%. 2. The method for releasing a silicone molded product according to claim 1, which uses a release layer sheet material as the release material. A method for releasing a molded product. 4. The method for releasing a silicone molded product according to claim 1, which uses a releasing material in which an adhesive is interposed between the releasing layer and the base material. 5. The method of releasing a silicone molded product according to claim 1, which uses a releasing material in which a barrier layer is provided in advance between the releasing layer and the base material. 6. A method for releasing a silicone molded product according to any one of claims 6 to 5, which uses a release material in which release layers are provided on both sides of the base material.