JP4737377B2 - Resin composition for release film and release film - Google Patents

Description

  The present invention relates to a release film resin composition and / or a release film. More specifically, the present invention relates to a release film having excellent release properties with respect to an adhesive and the like, and having little release agent release.

  The release film is a film-like material provided with a release surface that is laminated on the adhesive surface to protect the adhesive surface of the adhesive material when not in use, and is easily peeled without damaging the adhesive surface when in use. Widely used as a mount for adhesive tapes and labels. The release film usually includes a base material and a release layer containing a release agent provided on at least one surface of the base material. Paper, plastic film, etc. are used for the base material, and a silicone compound, a long-chain alkyl group-containing compound, etc. are used for the release agent. In such a release film, when the release agent is not sufficiently adhered to the substrate, the release agent is transferred to the adhesive surface of the tape or label when the tape or label is peeled off from the release film. And the stickiness of the label may be deteriorated.

  For this reason, as a method for producing a release film, a method in which a release agent such as vinyl group-containing polydimethylsiloxane is coated on a substrate and then the release agent is cured is generally used. However, in this method, there are problems that a large amount of an organic solvent is used to uniformly apply the release agent, and that the base material is exposed to a high temperature when the release agent is cured, so that pinholes are generated. It was happening.

  For this reason, a method for imparting releasability to a plastic as a base material instead of a coating method has been proposed.

  For example, a resin composition in which a silicone compound is added to polyethylene and a method for producing a release sheet have been proposed (see, for example, Patent Document 1). Examples of the silicone compound include dimethyl silicone oil, polymethylhydrogensiloxane, α-olefin having one vinyl group at the end, and chloroplatinic acid as a catalyst, followed by addition reaction by heating, and unreacted hydrogen. It is described that a group obtained by blocking a group, charging a catalyst and propylene, and heating / addition reaction is suitable. According to this method, although no organic solvent is used, it is difficult to control the peelability due to the progress of the addition reaction during extrusion molding, and at the same time the adhesive strength between the substrate and the resin composition is reduced. There's a problem.

  Further, a method of adding polydimethylsiloxane to polyethylene and irradiating it with an electron beam (for example, see Patent Document 2) and a method of irradiating with radiation (for example, see Patent Document 3) have been proposed. However, since these methods require expensive irradiation equipment, there is a problem of lack of versatility.

JP-A-6-41500 JP-A 63-249627 JP-A-5-269880

  The present invention has been made in view of the above situation, and does not require a coating step of a silicone compound containing an organic solvent, is excellent in extrusion processability, and does not deteriorate the adhesion to a substrate. An object of the present invention is to provide a release film resin composition and a release film comprising the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used an olefin-based resin composition containing a specific amount of polydimethylsiloxane having a specific amino group for a specific ethylene-based polymer. It has been found that a release film having excellent releasability and excellent cost performance can be produced, and the present invention has been completed.

  That is, the present invention relates to a release film comprising 95 to 99.99% by weight of an olefin polymer and 0.01 to 5% by weight of polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol to 50000 g / mol. The present invention relates to a resin composition, a release film comprising the same, and a laminate used.

  The present invention is described in detail below.

  The olefin polymer used in the present invention may be generally called a polyolefin resin, and such a polyolefin resin has 2 to 12 carbon atoms such as ethylene, propylene and 1-butene. An α-olefin homopolymer or copolymer is shown. For example, low density polyethylene, high density polyethylene, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, ethylene-4-methyl-1-pentene copolymer , Ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-based polymer such as ethylene-methacrylic acid ester copolymer, polypropylene , Propylene / ethylene copolymers, propylene polymers such as propylene / 1-butene copolymer, poly 1-butene, poly 1-hexene, poly 4-methyl-1-pentene, and the like. The combination may be used alone or in combination of two or more. Among such olefin polymers, an ethylene polymer is most preferable because of its excellent releasability, film moldability, and cost performance.

  Here, the polymerization method of the olefin polymer is not particularly limited, and low-density polyethylene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, ethylene / acrylic acid are used. In the case of an acid ester copolymer, an ethylene / methacrylic acid ester copolymer, etc., for example, a radical polymerization method by a high pressure method can be mentioned. Also, high density polyethylene, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, ethylene / 4-methyl-1-pentene copolymer, polypropylene, propylene In the case of ethylene copolymer, propylene / 1-butene copolymer, poly-1-butene, poly-1-hexene, poly-4-methyl-1-pentene, etc., a gas phase method using a Ziegler-Natta catalyst or a metallocene catalyst, Examples of the polymerization method include a solution method, a slurry method, and a high-pressure method.

  The olefin polymer used in the present invention is in accordance with JIS K6922-1 (1997) in consideration of film forming processability (for example, extrusion load, extensibility during film formation) when subjected to film forming processing. It is preferable that MFR is in the range of 0.1 to 50 g / 10 min.

The olefin polymer has a density measured by JIS K6922-1 (1997) of 880 to 970 kg / m ³ in consideration of heat resistance of the release film, adhesive strength between the pressure sensitive adhesive and the release film, and the like. It is preferable to be in the range.

  The polydimethylsiloxane (A) used in the present invention has an amino group equivalent of 500 g / mol or more and 50000 g / mol or less. When the amino group equivalent is less than 500 g / mol, the release property of the release film is inferior, and when the amino group equivalent exceeds 50,000 g / mol, the adhesion between the polydimethylsiloxane (A) and the olefin polymer is insufficient. This is not preferable because the release layer is rub off. Moreover, since the adhesiveness with respect to base materials, such as paper, is inferior in the laminated body formed by extrusion lamination molding etc., it is unpreferable.

  As the polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol or more and 50000 g / mol or less used in the present invention, a polydimethylsiloxane (A) having a viscosity at 25 ° C. of 50 cSt or more is preferable because the weight loss during extrusion molding is small.

  Polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol or more and 50000 g / mol or less used in the present invention is, for example, trade names SF-8417, BY16-208, BY16- from Toray Dow Corning Silicone Co., Ltd. 880, BY16-750, etc. are commercially available.

  The polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol or more and 50000 g / mol or less used in the present invention is blended in the release film resin composition in an amount of 0.01 to 5% by weight. When the blending ratio of the polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol or more and 50000 g / mol or less is less than 0.01% by weight, the amount of the polydimethylsiloxane (A) oozed onto the film surface is small, The release property of the release film is inferior, which is not preferable. On the other hand, if it exceeds 5% by weight, the amount of the polydimethylsiloxane (A) leached onto the film surface becomes excessive, and the re-adhesiveness of the pressure-sensitive adhesive adhered to the release film is impaired. Further, the resin may slip in the extruder and may not be formed into a film.

  Moreover, the resin composition for mold release films of this invention may mix | blend the polydimethylsiloxane (B) which has an epoxy group and / or a carboxyl group as needed. It is preferable to include polydimethylsiloxane (B) having an epoxy group and / or a carboxyl group because surface contamination of the pressure-sensitive adhesive is prevented. Examples of such polydimethylsiloxane having an amino group and / or a carboxyl group are commercially available from Toray Dow Corning Silicone Co., Ltd. under the trade names SF-8417, BY16-208, BY16-880, BY16-750, and the like. .

  The polydimethylsiloxane (B) having an epoxy group and / or carboxyl group used in the present invention has an amino group equivalent of 500 g / mol or more and 50000 g when the functional group equivalent is 50 g / mol or more and less than 500 g / mol. This is preferable because the curing reaction of polydimethylsiloxane having a concentration of at most / mol can be accelerated. By promoting the curing reaction, the adhesion between the olefin polymer and the polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol to 50000 g / mol is improved. Sexual deterioration can be prevented.

In addition, the resin composition for a release film of the present invention includes additives usually used for olefin resins such as an antioxidant, a lubricant, a neutralizing agent, an antiblocking agent, a surfactant, and a slip agent as necessary. May be added.
The resin composition for a release film of the present invention can be produced with a resin mixing apparatus that is usually used. For example, a single-screw extruder, a twin-screw extruder, a Banbury mixer, a pressure kneader, a melt kneader such as a rotating roll, a Henschel mixer, a V blender, a ribbon blender, a tumbler, and the like can be given. When using a melt-kneading apparatus, the melting temperature is preferably about the melting point of the olefin polymer to about 350 ° C.

  The release film of the present invention can be produced using the resin composition for a release film of the present invention using an inflation molding machine, a T die cast molding machine, a calendar molding machine, a press molding machine, or the like. In inflation molding and T-die casting, it is also possible to obtain a laminate by coextrusion, and to obtain a laminate by laminate molding such as extrusion laminate molding, coextrusion laminate molding, dry laminate molding, and thermal laminate molding. Is also possible. When using an inflation molding machine, a T-die casting machine, a calendar molding machine, or a press molding machine, the resin temperature is preferably 150 ° C to 300 ° C, and when using an extrusion laminate molding machine, 250 ° C to 350 ° C is preferred. .

  Moreover, as a base material which comprises a laminated body, a synthetic polymer film or sheet, a woven fabric, a nonwoven fabric, paper, metal foil, etc. are mentioned. As a synthetic polymer film or sheet, for example, a film or sheet made of a synthetic polymer such as polyester such as polyethylene terephthalate, polyamide, polyvinyl alcohol, saponified ethylene / vinyl acetate copolymer, polycarbonate, polyethylene, polypropylene, etc. Is mentioned. Further, these high polymer films or sheets may be further subjected to aluminum vapor deposition or alumina vapor deposition. Further, these polymer films or sheets may be further printed using urethane ink or the like. Examples of the woven fabric and non-woven fabric include those made of synthetic resin such as polyester, polyethylene, and polypropylene, or those made of natural materials such as sufu. Examples of the paper include craft paper, kulpack paper, high-quality paper, glassine paper, and paperboard.

  The thickness of the release film of the present invention is not particularly limited as long as the object of the present invention is achieved, and is preferably 1 μm to 5 mm in thickness because of excellent flexibility and less problems such as breakage.

  The release film of the present invention is preferably one in which at least one surface of the release film is oxidized in order to suppress transfer of the release agent to the adhesive surface of the tape or label. Further, the peeling strength is reduced by the oxidation, and the releasability can be improved.

  Oxidation treatment methods for oxidizing the film surface include chromic acid treatment, sulfuric acid treatment, air oxidation, ozone treatment, corona discharge treatment, flame treatment, plasma treatment, etc., and oxides are effectively applied to the polyolefin resin surface. In order to form it, corona discharge treatment, flame treatment, plasma treatment and the like are preferable.

Corona discharge treatment is widely used as a continuous treatment technique for plastic film and sheet surfaces, and is performed by passing the film through a corona atmosphere generated by a corona discharge treatment machine. The corona discharge density is preferably 1 to 100 W · min / m ² because of excellent re-tackiness of the pressure-sensitive adhesive.

  The flame treatment is performed by bringing the film surface into contact with a flame generated when natural gas, propane, or the like is burned.

  Plasma treatment is an excited inert gas that is electrically neutral after removing charged particles by electronically exciting a single or mixed gas such as argon, helium, neon, hydrogen, oxygen, and air with a plasma jet. Is sprayed onto the film surface.

  A release film using the resin composition for a release film of the present invention is extremely useful as a wide range of industrial materials such as labels, release paper and tape for sealing.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

  The measurement methods and evaluation methods for physical properties and workability are shown below.

(1) Melt mass flow rate (MFR)
It measured based on JISK6922-1 (1997).

(2) Density The density was measured in accordance with JIS K6922-1 (1997).

(3) Release property A 50 mm wide and 150 mm long cloth adhesive tape (trade name cloth adhesive tape No. 3310, manufactured by Sliontec Co., Ltd.) was applied to the surface of the release film side of the laminate obtained in the examples, and the linear pressure After passing between the rubber rolls under conditions of 5 kg / cm and a speed of 5 m / min, it was left in an atmosphere at 40 ° C. for 7 days to obtain a sample for measuring releasability. Thereafter, the sample was cut to a width of 15 mm, and the adhesive strength between the cloth adhesive tape and the release film was measured with a tensile tester (Autograph DCS-100, manufactured by Shimadzu Corporation). The peeling speed is 300 mm / min.

(4) Re-adhesive property The cloth adhesive tape having a width of 15 mm peeled from the surface of the release film by the above-described releasability test was applied to an aluminum plate (trade name A1N30H-H18, manufactured by Toyo Aluminum Co., Ltd., thickness 0.1 mm) at 5 kg / cm. Affixed at a linear pressure of. After leaving in an atmosphere of 23 ° C. for 1 day, the adhesive strength between the cloth adhesive tape and the aluminum plate was measured with a tensile tester (Autograph DCS-100, manufactured by Shimadzu Corporation). The peeling speed is 300 mm / min. When the pressure-sensitive adhesive surface of the pressure-sensitive adhesive tape is contaminated by the release film, the re-adhesiveness of the pressure-sensitive adhesive tape is lowered and the performance as the pressure-sensitive adhesive tape is impaired. That is, it is preferable that the re-adhesion strength is higher.

(5) Adhesiveness with substrate The adhesive strength between the paper and the release film of the laminate obtained in the example was measured with a tensile tester (manufactured by Shimadzu Corporation, Autograph DCS-100). The peeling speed is 300 mm / min, and the width of the test piece is 15 mm. It can be said that the adhesiveness to the base material is good if it is adhered to such an extent that the material of the paper as the base material is destroyed.

Example 1
As an olefin polymer, low-density polyethylene (product name Petrocene 213 manufactured by Tosoh Corp., hereinafter sometimes referred to as LDPE) having an MFR of 8 g / 10 min and a density of 918 kg / m ³ is 99% by weight, amino group equivalent As the polydimethylsiloxane (A) having an amino group equivalent of 1800 g / mol and a viscosity of 1200 cSt as a polydimethylsiloxane (A) having a molecular weight of 500 g / mol to 50000 g / mol, trade name SF8417 manufactured by Toray Dow Corning Silicone Co., Ltd. In the following, A-1) may be blended so as to be 1% by weight, and melt-kneaded (kneading temperature 150 ° C.) with a single screw extruder (Placo Corporation diameter 50 mm) to provide a resin composition for a release film A product pellet was obtained.

The obtained pellets were supplied to an extruder of an extrusion laminator having a screw of 25 mmφ, extruded from a T die at a temperature of 305 ° C., and a high-quality paper (Hokuetsu) subjected to corona treatment under the condition of 50 W · min / m ² as a base material. Laminate is obtained by laminating the resin composition for a release film to a thickness of 20 μm on a corona-treated surface of a product name Kinmari SW (basis weight 50 g / m ² ) manufactured by Paper Manufacturing Co., Ltd., and then releasing the laminate. The surface of the mold film resin composition was subjected to corona treatment under the condition of 30 W · min / m ² to obtain a release film.

  After the obtained laminate was stored in an oven kept at 40 ° C. for 20 hours, the releasability, re-tackiness, and adhesion to the substrate were measured, and the measurement results are shown in Table 1.

実施例２
オレフィン系重合体として、ＬＤＰＥを９９重量％、アミノ変性ポリジメチルシロキサン（Ａ−１）を１重量部とする代わりに、ＬＤＰＥを９９．５重量％、アミノ変性ポリジメチルシロキサン（Ａ−１）を０．５重量％とした以外は実施例１と同様にして離型フィルムを得た。評価結果は表１に示した。

Example 2
As an olefin polymer, instead of using 99% by weight of LDPE and 1 part by weight of amino-modified polydimethylsiloxane (A-1), 99.5% by weight of LDPE and amino-modified polydimethylsiloxane (A-1) A release film was obtained in the same manner as in Example 1 except that the content was 0.5% by weight. The evaluation results are shown in Table 1.

Example 3
As an olefin polymer, instead of making LDPE 99% by weight and amino-modified polydimethylsiloxane (A-1) 1 part by weight, LDPE 98% by weight and amino-modified polydimethylsiloxane (A-1) 2%. A release film was obtained in the same manner as in Example 1 except that the percentage was changed to%. The evaluation results are shown in Table 1.

Example 4
As an olefin polymer, instead of making 99% by weight of LDPE and 1 part by weight of amino-modified polydimethylsiloxane (A-1), 99% by weight of LDPE and 1% of amino-modified polydimethylsiloxane (A-1) % Polydimethylsiloxane (B-1) having an epoxy group having a functional group equivalent of 350 g / mol (trade name Shin-Etsu Silicone KF101, manufactured by Shin-Etsu Chemical Co., Ltd., hereinafter B) A release film was obtained in the same manner as in Example 1 except that 0.1 part by weight of -1 was added). The evaluation results are shown in Table 1.

Example 5
As an olefin polymer, 99% by weight of LDPE, 99% by weight of LDPE and 1% by weight of amino-modified polydimethylsiloxane (A-1) instead of 1 part by weight of amino-modified polydimethylsiloxane (A-1) Polydimethylsiloxane (B-2) having a carboxyl group having a functional group equivalent weight of 750 g / mol with respect to 100 parts by weight of the composition consisting of: Toray Dow Corning Silicone Co., Ltd., trade name BY16-750, Hereinafter, a release film was obtained in the same manner as in Example 1 except that 0.1 part by weight of B-2) was sometimes added. The evaluation results are shown in Table 1.

Example 6
As an olefin polymer, 99% by weight of LDPE, 99% by weight of LDPE and 1% by weight of amino-modified polydimethylsiloxane (A-1) instead of 1 part by weight of amino-modified polydimethylsiloxane (A-1) Polydimethylsiloxane (B-3) having a carboxyl group having a functional group equivalent of 3200 g / mol with respect to 100 parts by weight of the composition consisting of: Toray Dow Corning Silicone Co., Ltd., trade name SF8411, A release film was obtained in the same manner as in Example 1 except that 0.1 part by weight of (sometimes referred to as B-3) was added. The evaluation results are shown in Table 1.

Example 7
As an olefin polymer, instead of LDPE, an ethylene / 1-octene copolymer having a MFR of 7.5 g / 10 min and a density of 902 kg / m ³ (trade name Affinity PT1450 manufactured by Dow Chemical, hereinafter referred to as C8LL) Except for the above, a release film was obtained in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 1
As the olefin polymer, a release film was prepared in the same manner as in Example 1 except that 99% by weight of LDPE and 1% by weight of amino-modified polydimethylsiloxane (A-1) were replaced by 100% by weight of LDPE. Obtained. The evaluation results are shown in Table 2, but the adhesive strength between the cloth adhesive tape and the release film was high, and the release property was inferior. Moreover, the adhesive remained on the release film surface, and the adhesiveness was inferior.

比較例２
オレフィン系重合体として、ＬＤＰＥを９９重量％、アミノ変性ポリジメチルシロキサンを１重量部の代わりに、ＬＤＰＥを９４重量％、アミノ変性ポリジメチルシロキサンを６重量％とした以外は実施例１と同様にして離型フィルムの製造を試みたが、押出不良のためフィルムを得ることができなかった。

Comparative Example 2
As the olefin polymer, the same procedure as in Example 1 was performed except that LDPE was changed to 99% by weight, amino-modified polydimethylsiloxane was replaced by 1 part by weight, and LDPE was changed to 94% by weight and amino-modified polydimethylsiloxane was changed to 6% by weight. Attempts were made to produce a release film, but the film could not be obtained due to poor extrusion.

Comparative Example 3
As an olefin polymer, 99% by weight of LDPE and 99% by weight of LDPE instead of 1% by weight of amino-modified polydimethylsiloxane (A-1), a poly having an epoxy group with a functional group equivalent of 350 g / mol. A release film was obtained in the same manner as in Example 1 except that 1% by weight of dimethylsiloxane (B-1) was changed. The evaluation results are shown in Table 2, but the adhesive strength between the cloth adhesive tape and the release film was high, and the release property was inferior. Moreover, the adhesive remained on the release film surface, and the adhesiveness was inferior.

Comparative Example 4
As an olefin polymer, instead of 99% by weight of LDPE and 1% by weight of amino-modified polydimethylsiloxane (A-1), 99% by weight of LDPE and poly having a carboxyl group with a functional group equivalent of 750 g / mol. A release film was obtained in the same manner as in Example 1 except that 1% by weight of dimethylsiloxane (B-2) was changed. The evaluation results are shown in Table 2, but the adhesive strength between the cloth adhesive tape and the release film was high, and the release property was inferior. Moreover, the adhesive remained on the release film surface, and the adhesiveness was inferior.

Claims (8)

With respect to 100 parts by weight of a composition comprising 95 to 99.99% by weight of an olefin polymer and 0.01 to 5% by weight of polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol to 50000 g / mol, A resin composition for a release film comprising 0.001 to 2.5 parts by weight of polydimethylsiloxane (B) having an epoxy group and / or a carboxyl group. The weight ratio [(A) / (B)] of the polydimethylsiloxane (A) having an amino group equivalent of 500 g / mol to 50000 g / mol and the polydimethylsiloxane (B) having an epoxy group and / or a carboxyl group is 1000. The resin composition for a release film according to claim 1, wherein the resin composition is in the range of: 1 to 2: 1 (weight ratio). The olefin polymer has a melt mass flow rate measured in accordance with JIS K6922-1 (1999) of 0.1 to 50 g / 10 min, and a density measured in accordance with JIS K6922-1 (1999) of 880 to 970 kg / m ³ . The resin composition for a release film according to claim 1, wherein the resin composition is a release film. A release film comprising the release film resin composition according to any one of claims 1 to 3. The release film according to claim 4, wherein at least one surface is oxidized. 6. The release film according to claim 5 , wherein the oxidation treatment is at least one treatment method selected from the group consisting of corona discharge treatment, flame treatment, and plasma treatment. A laminate comprising at least one release film according to any one of claims 4 to 6 . The laminate according to claim 7 , wherein the laminate is laminated with one or more base materials selected from paper, cloth, woven fabric made of synthetic resin, or nonwoven fabric.