JP5210524B2 - Adhesive body and method for producing adhesive body - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive body used for pressure-sensitive adhesive labels and the like, and particularly relates to a pressure-sensitive adhesive body to which a pressure-sensitive adhesive is applied in-line.

  Adhesives such as pressure-sensitive adhesive labels are, for example, a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer on one side of a pressure-sensitive adhesive sheet substrate, a pressure-sensitive adhesive sheet on one side of the pressure-sensitive adhesive sheet base material, and a release agent. It is configured to be adhered so that the adhesive layer is in contact with the layer. The pressure-sensitive adhesive body is demanded to reduce the burden on the environment and improve productivity. In order to meet these demands, a solventless type silicone is being used as a release agent in recent years. Solventless silicone does not use an organic solvent, so it can be expected to reduce environmental burdens, and can be coated at a higher speed than solvent type, so that productivity can be expected.

From similar demands, it has been attempted to use acrylic emulsion adhesives that do not use organic solvents as adhesives. In particular, the coating properties of adhesives have been improved to enable high-speed coating. In order to achieve this, use of a low-viscosity emulsion adhesive is being studied (for example, Patent Documents 1 to 3).
JP 2003-126762 A JP 2003-96413 A JP 2001-181590 A

  By the way, in order to improve productivity, the pressure-sensitive adhesive and the release agent are continuously applied without being rolled up after the release agent is applied to one surface of the release sheet base material and a release agent layer is provided. It is preferable to apply a pressure-sensitive adhesive on the layer, so-called in-line. However, when a low-viscosity emulsion pressure-sensitive adhesive is applied onto a solvent-free silicone release agent layer, there is a problem that a portion where the pressure-sensitive adhesive is uncoated, that is, so-called glue repellency is likely to occur.

  Therefore, the present invention has been made in view of such problems, and even when a low-viscosity emulsion adhesive is applied on a solvent-free silicone release agent layer, adhesive repelling is less likely to occur. The purpose is to provide a body.

  The pressure-sensitive adhesive body according to the present invention has a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer on one surface of a pressure-sensitive adhesive sheet base material, and a pressure-sensitive adhesive sheet provided on one surface of the pressure-sensitive adhesive sheet base material. In the pressure-sensitive adhesive body that is adhered and configured so that the pressure-sensitive adhesive layer is in contact, the pressure-sensitive adhesive layer is coated with an emulsion pressure-sensitive adhesive having a viscosity of 100 to 2000 mPa · s before coating on the release agent layer. The release agent layer is formed of a low molecular weight organopolysiloxane having at least two alkenyl groups in one molecule having a mass average molecular weight of 1000 to 20,000, and a high molecular weight having a mass average molecular weight of 50,000 to 500,000. An addition reaction solventless release agent composition containing a molecular linear organopolysiloxane is formed by curing coating.

  The viscosity of the release agent composition before curing is, for example, 50 to 3000 mPa · s. In addition, the polymer linear organopolysiloxane has, for example, 1 to 3 alkenyl groups only at each molecular end in one molecule or no alkenyl group.

  The pressure-sensitive adhesive body production method according to the present invention is a pressure-sensitive adhesive body manufacturing method in which a pressure-sensitive adhesive is applied on a release agent layer formed on one surface of a release sheet substrate to form a pressure-sensitive adhesive layer. The agent is an emulsion adhesive having a viscosity of 100 to 2000 mPa · s before coating, and the release agent layer has at least two alkenyl groups in one molecule having a mass average molecular weight of 1000 to 20,000. It is formed by curing and coating an addition reaction type solventless release agent composition comprising a low molecular weight organopolysiloxane and a high molecular weight linear organopolysiloxane having a mass average molecular weight of 50,000 to 500,000. And

  In the present invention, by adding a linear organopolysiloxane having a high molecular weight to the release agent composition, the coating property of the release agent layer of the low-viscosity emulsion adhesive is improved. Can be prevented. Moreover, since the adhesive is composed of an emulsion and the release agent is a solvent-free system, it is not necessary to use an organic solvent for both the adhesive layer and the release agent layer. it can.

Hereinafter, the present invention will be described in more detail using embodiments.
FIG. 1 is a schematic cross-sectional view showing an adhesive body according to an embodiment of the present invention. The pressure-sensitive adhesive body 10 is peeled off from a pressure-sensitive adhesive sheet 23 having a pressure-sensitive adhesive layer 22 on one surface of a pressure-sensitive adhesive sheet base material 21 and a pressure-sensitive adhesive sheet 23 having a pressure-sensitive adhesive layer 22 on one surface of the pressure-sensitive adhesive sheet base material 21. The adhesive layer 12 is adhered and configured so as to be in contact with the adhesive layer 22.

  The release sheet 13 is coated on the release sheet substrate 11 with an addition-reaction type solventless release agent composition, and then cured by thermal curing to form a release agent layer 12 on the release sheet substrate 11. It is produced by forming. On the release agent layer 12 of the release sheet 13, the adhesive layer 22 is formed in a so-called in-line, that is, the adhesive layer 22 is formed by continuously applying the adhesive to the release agent layer 12. On the pressure-sensitive adhesive layer 22, a pressure-sensitive adhesive sheet substrate 21 is further adhered, whereby the pressure-sensitive adhesive body 10 is manufactured.

  In addition, as a method of applying the release agent composition on the release sheet substrate 11 and continuously applying the adhesive on the formed release agent layer 12, for example, a gravure coating method, a bar coating method, A tandem coating method that combines existing methods such as spray coating, spin coating, knife coating, roll coating, and die coating can be used.

  The release sheet substrate 11 has a function of supporting the release agent layer 12. For example, a polyester film such as a polyethylene terephthalate film or a polybutylene terephthalate film, a polyolefin film such as a polypropylene film or a polymethylpentene film, or a polycarbonate film Plastic film such as aluminum, stainless steel and other metal foils, glassine paper, high quality paper, coated paper, impregnated paper, synthetic paper, etc., and these paper base materials laminated with a thermoplastic resin such as polyethylene. ing.

The basis weight of the release sheet base material 11 is not particularly limited, but is preferably 5~300g / ^{m 2,} and more preferably 10 to 200 g / ^{m 2.}

  The solventless type release agent composition for forming the release agent layer 12 comprises a low-molecular-weight organopolysiloxane as a main polymer, and a polymer linear organopolysiloxane, a crosslinking agent, and a catalyst are added. If desired, a reaction inhibitor, a release modifier, an adhesion improver, and the like may be added. In addition, in the curing step after applying the release agent, when performing ultraviolet irradiation in addition to heating, a photoinitiator may be added.

  As the low molecular weight organopolysiloxane, an organopolysiloxane having at least two alkenyl groups in one molecule having a mass average molecular weight of 1000 to 20,000 is used. The organopolysiloxane is represented by, for example, the general formula (I). .

R ¹ R ² ₂ SiO (RRSiO) _m (RR ² SiO) _n SiR ² ₂ R ¹ (I)
Here, R is the same or different monovalent hydrocarbon having no aliphatic unsaturated bond, R ¹ is an alkenyl group, R ² is R or R ¹ , m and n represent natural numbers, and 12 ≦ (m + n ) ≦ 270.

Examples of the alkenyl group represented by R ¹ include those having 2 to 10 carbon atoms such as a vinyl group, an allyl group, a propenyl group, and a hexenyl group. R has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and examples thereof include alkyl groups such as a methyl group, an ethyl group and a propyl group, and aryl groups such as a phenyl group and a tolyl group. From this point, it is preferable that 80 mol% or more is a methyl group. The viscosity of the low molecular organopolysiloxane is, for example, 10 to 300 mPa · s.

  As the polymer linear organopolysiloxane, for example, one having 1 to 3 alkenyl groups only at the end of each molecular chain in one molecule or one having no alkenyl groups is used. The one shown in is used.

R ³ ₃ SiO (R ₂ SiO) _p SiR ³ ₃ (II)
Here, R is the same or different monovalent hydrocarbon having no aliphatic unsaturated bond, R ³ is an alkenyl group such as a vinyl group, or the same or different monovalent hydrocarbon group, and p represents a natural number. 700 ≦ p ≦ 7000.

  As shown by the general formula (II), the polymer linear organopolysiloxane preferably has 1 to 3 alkenyl groups only at the end of each molecular chain or has no alkenyl groups. The mass average molecular weight of the polymer linear organopolysiloxane is 50,000 to 500,000, preferably 70,000 to 500,000, more preferably 100,000 to 500,000. When the molecular weight is lower than the above lower limit value, adhesive repellency is likely to occur in the pressure-sensitive adhesive applied on the release agent layer 12 at a high speed, and the adhesiveness of the pressure-sensitive adhesive layer 22 tends to decrease. Moreover, it is difficult to synthesize silicone having a molecular weight exceeding the upper limit.

  Specific examples of the polymer linear organopolysiloxane include, for example, dimethylpolysiloxane and organopolysiloxane having one vinyl group only at each molecular chain terminal. The polymer linear organopolysiloxane is preferably added in an amount of 0.5 to 15 parts by mass, particularly preferably 0.8 to 12 parts by mass with respect to 100 parts by mass of the low molecular organopolysiloxane.

  As a crosslinking agent, for example, polyorganohydrogensiloxane having at least two silicon-bonded hydrogen atoms (SiH) in one molecule, specifically, dimethylhydrogensiloxy group end-capped dimethylsiloxane-methylhydrogensiloxane copolymer Examples thereof include a compound, a trimethylsiloxy group end-capped dimethylsiloxane-methylhydrogensiloxane copolymer, a trimethylsiloxy group end-capped poly (methylhydrogensiloxane), and poly (hydrogensilsesquioxane). In this embodiment, a cured film is formed by an addition reaction between the crosslinking agent SiH and the alkenyl group of the low-molecular-weight organopolysiloxane and the high-molecular-weight linear organopolysiloxane.

  The crosslinking agent is preferably added so that the number of silicon-bonded hydrogen atoms is 1.0 to 3.0 (molar ratio) with respect to the number of alkenyl groups in the release agent composition. When the molar ratio is lower than 1.0, the curability of the composition is lowered. When the molar ratio is higher than 3.0, the peeling force of the release agent becomes heavy, and the peeling performance may be deteriorated.

  As the catalyst, for example, a platinum compound is used. Examples of the platinum compound include fine platinum, fine platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, and chloroplatinic acid. Examples include olefin complexes, palladium, and rhodium catalysts. About 1 to 1000 ppm of the catalyst is added as a platinum-based metal with respect to the total amount of the addition reaction type organopolysiloxane and the crosslinking agent.

  The viscosity of the release agent composition before curing is preferably 50 to 3000 mPa · s, more preferably 80 to 2500 mPa · s, and particularly preferably 100 to 2000 mPa · s. When the viscosity is lower than the above lower limit value, the release agent composition tends to penetrate into the base material when paper is used for the release sheet base material, and when the viscosity is higher than the upper limit value, it is difficult to apply the release agent composition to the base material. Become.

The coating amount of the release agent layer 12 is not particularly limited, but is preferably 0.05-5 g / ^{m 2,} and more preferably 0.1 to 3 g / ^{m 2.}

  The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 22 is not particularly limited as long as it is an emulsion pressure-sensitive adhesive, but an acrylic emulsion pressure-sensitive adhesive is preferably used. The acrylic emulsion pressure-sensitive adhesive is composed mainly of an acrylic copolymer obtained by copolymerizing a functional group-containing monomer and another monomer such as an acrylic ester or methacrylic ester, and water as a solvent. Contains desired additives such as emulsifiers, thickeners, etc., as necessary, stabilizers, tackifiers, fillers, colorants, antioxidants, antistatic agents, ultraviolet absorbers, etc. May further be included. Examples of the functional group-containing monomer include carboxyl group-containing monomers such as acrylic acid and methacrylic acid. It is preferable that a functional group containing monomer contains 0.3-5.0 mass% on the basis (100 mass%) of the whole monomer which comprises an acrylate-type copolymer. By making the content of the functional group-containing monomer 5.0% by mass or less, it is possible to suppress an increase in the peeling force of the release sheet 13 with time.

  The viscosity of the pressure-sensitive adhesive before being applied to the release agent layer 12 is set to a range of 100 to 2000 mPa · s, preferably 150 to 1500 mPa · s, and particularly preferably 200 to 1200 mPa · s. If the viscosity is too low, glue repelling occurs even when an adhesive is applied on the release agent layer 12 having a good silicone formulation, and if it is too high, high-speed coating becomes difficult.

The coating amount of the adhesive layer 22 is not particularly limited, but is preferably 5 to 60 g / ^{m 2,} and more preferably 10 to 40 g / ^{m 2.}

  The pressure-sensitive adhesive sheet substrate 21 has a function of sticking to the pressure-sensitive adhesive layer 22 and supporting the pressure-sensitive adhesive layer 22. For example, paper such as fine paper, craft paper, glassine paper, synthetic paper, polyethylene terephthalate film, It is composed of a single or composite material such as a polybutylene terephthalate film, a polyethylene film, a polypropylene film, a polymethylpentene film, a plastic film such as a polycarbonate film, or a metal foil such as aluminum or stainless steel. The pressure-sensitive adhesive sheet substrate 21 may be subjected to surface treatment for the purpose of improving the adhesion of the printing ink or the pressure-sensitive adhesive layer 22 on the front surface or the back surface thereof.

  In this specification, the viscosity is measured at 25 ° C. in accordance with JIS K7117-1 4.1 (Brookfield rotary viscometer).

Moreover, a mass average molecular weight means what measured each silicone resin by gel permeation chromatography (GPC), and calculated | required it as a polystyrene conversion value. The measurement conditions are as follows.
GPC measuring device: Shodex GPC SYSTEM-21H (trade name, manufactured by Showa Denko)
Column: Two Waters, styragel (R) HR5E used Measurement solvent: Chloroform Measurement temperature: 40 ° C
Flow rate: 1.0 ml / min Sample concentration: 1.0%

  The present embodiment will be described below using examples, but the present invention is not limited to the configurations of the following examples.

[Example 1]
A mixture of low molecular weight organopolysiloxane (containing 5 vinyl groups in one molecule, weight average molecular weight 8000) and polyorganohydrogensiloxane (molar ratio of silicon-bonded hydrogen atoms to alkenyl groups in the mixture). 8) To 100 parts by mass, 5 parts by mass of dimethylpolysiloxane having a mass average molecular weight of 4.0 × 10 ⁵ is added as a polymer linear organopolysiloxane, and 3-methyl-1-butyne as a reaction inhibitor is further added. 0.1 part by mass of 3-ol and 1 part by mass of a platinum catalyst (trade name: SRX-212, manufactured by Toray Dow Corning) were added to obtain a solventless release agent composition. The viscosity of the release agent composition was 500 mPa · s. Next, glassine paper having a basis weight of 80 g / m ² is prepared as a release sheet substrate, and the release agent composition is uniformly applied to the substrate using a gravure coater so that the application amount is 1.0 g / m ^2. Then, it was heated and cured at 140 ° C. to obtain a release sheet in which a release agent layer was formed on one surface of the substrate.

Next, on the release agent layer of the release sheet, an acrylic ester copolymer (monomer composition: acrylic acid-2-ethylhexyl 49% by mass, butyl acrylate 50% by mass, acrylic acid 1% by mass), The acrylic emulsion pressure-sensitive adhesive whose viscosity was adjusted to 500 mPa · s was applied at a coating speed of 150 m / min using a gravure coater so that the coating amount after drying was 30 g / m ² .

[Example 2]
As the polymer linear organopolysiloxane, instead of dimethylpolysiloxane, the weight average molecular weight having one vinyl group at the end of each molecular chain (that is, two vinyl groups in one molecule) is 4.0 ×. The same operation as in Example 1 was carried out except that 5 parts by mass of 10 ⁵ organopolysiloxane was added. In addition, the viscosity of the release agent composition was 500 mPa · s.

[Example 3]
The same operation as in Example 2 was carried out except that the amount of the polymer linear organopolysiloxane added was 7 parts by mass. The viscosity of the release agent composition was 1500 mPa · s.

[Example 4]
The same operation as in Example 2 was carried out except that the amount of the polymer linear organopolysiloxane added was 2 parts by mass. The viscosity of the release agent composition was 300 mPa · s.

[Example 5]
The same operation as in Example 2 was carried out except that the amount of the polymer linear organopolysiloxane added was 1 part by mass. The viscosity of the release agent composition was 250 mPa · s.

[Example 6]
The same operation as in Example 1 was performed except that dimethylpolysiloxane having a mass average molecular weight of 1.0 × 10 ⁵ was used as the polymer linear organopolysiloxane. The viscosity of the release agent composition was 250 mPa · s.

[Example 7]
This was carried out in the same manner as in Example 1 except that dimethylpolysiloxane having a mass average molecular weight of 6.0 × 10 ⁴ was used as the polymer chain organopolysiloxane. The viscosity of the release agent composition was 200 mPa · s.

[Example 8]
The same procedure as in Example 2 was performed except that the addition amount of the thickener was adjusted and the viscosity of the adhesive was 200 mPa · s.

[Example 9]
The same procedure as in Example 2 was performed except that the addition amount of the thickener was adjusted and the viscosity of the pressure-sensitive adhesive was 1000 mPa · s.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that the high-molecular linear organopolysiloxane was not added. The viscosity of the release agent composition was 150 mPa · s.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that 5 parts by mass of dimethylpolysiloxane having a mass average molecular weight of 3.0 × 10 ³ was added instead of the polymer linear organopolysiloxane. The viscosity of the release agent composition was 170 mPa · s.

[Evaluation method]
In each of the examples and comparative examples, the number of repellants generated when the adhesive was applied on the release agent layer was detected using a defect detector. In this measurement, the number of repels at a width of 1000 mm and a length of 3000 m was measured. An adhesive-uncoated part having a diameter of 1 mm or more was repelled, and if the repelling size was less than 3 mm and the number of repellings was 10 or less, the coating was good and the result was marked as ◯ in Table 1. In the case of 11-30 pieces, it was set as Δ as being usable. In the case of 31 or more, x was marked as being unusable due to excessive repelling. Moreover, it was set as x when the size of a cistern was 3 mm or more in diameter.

  As is clear from Table 1, in Comparative Examples 1 and 2 in which the polymer linear organopolysiloxane having a mass average molecular weight of 50,000 to 500,000 was not added, a large amount of repellency was generated and the coatability was improved. There was a problem. In contrast, in Examples 1 to 9, in which a high-molecular-weight linear organopolysiloxane having a mass average molecular weight of 50,000 to 500,000 was added to a low-molecular-weight organopolysiloxane, almost no repelling occurred when the adhesive was applied. It can be understood that the coatability was good.

It is typical sectional drawing which shows the adhesive sheet which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Adhesive body 11 Release sheet base material 12 Release agent layer 13 Release sheet 21 Adhesive sheet base material 22 Adhesive layer 23 Adhesive sheet

Claims (4)

A pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer on one surface of a pressure-sensitive adhesive sheet base material is brought into contact with a pressure-sensitive adhesive sheet on one surface of the pressure-sensitive adhesive sheet base material, and the pressure-sensitive adhesive layer is in contact with the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive body that is adhered and configured,
The pressure-sensitive adhesive layer is a pressure-sensitive adhesive formed by applying an emulsion pressure-sensitive adhesive having a viscosity before coating of 100 to 2000 mPa · s to the release agent layer,
The release agent layer comprises a low molecular weight organopolysiloxane having a mass average molecular weight of 1000 to 20,000 represented by the following general formula (I) and a high molecular weight linear organopolysiloxane having a mass average molecular weight of 50,000 to 500,000. A pressure-sensitive adhesive body comprising a cured film of an addition reaction type solventless release agent composition comprising:
R ¹ R ² ₂ SiO (RRSiO) _m (RR ² SiO) _n SiR ² ₂ R ¹ (I)
(Wherein R is the same or different monovalent hydrocarbon having no aliphatic unsaturated bond, R ¹ is an alkenyl group, R ² is R or R ¹ , and m and n represent natural numbers. 12 ≦ (m + n) ≦ 270.)   The pressure-sensitive adhesive body according to claim 1, wherein the release agent composition has a viscosity before curing of 50 to 3000 mPa · s.   The pressure-sensitive adhesive according to claim 1, wherein the polymer linear organopolysiloxane has 1 to 3 alkenyl groups only at each molecular end in one molecule, or has no alkenyl groups. body. In the method for producing a pressure-sensitive adhesive body, a pressure-sensitive adhesive layer is formed by applying a pressure-sensitive adhesive on a release layer formed on one surface of a release sheet substrate.
The pressure-sensitive adhesive is an emulsion pressure-sensitive adhesive having a viscosity of 100 to 2000 mPa · s before coating,
The release agent layer is composed of a low molecular weight organopolysiloxane having a mass average molecular weight of 1000 to 20,000 represented by the following general formula (I) and a high molecular weight linear organopolysiloxane having a mass average molecular weight of 50,000 to 500,000. A method for producing a pressure-sensitive adhesive body comprising forming a cured coating of an addition reaction type solventless release agent composition comprising:
R ¹ R ² ₂ SiO (RRSiO) _m (RR ² SiO) _n SiR ² ₂ R ¹ (I)
(Wherein R is the same or different monovalent hydrocarbon having no aliphatic unsaturated bond, R ¹ is an alkenyl group, R ² is R or R ¹ , and m and n represent natural numbers. 12 ≦ (m + n) ≦ 270.)