JP6283029B2 - Adhesive composition and adhesive sheet - Google Patents

Description

  The present invention relates to a novel pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet containing the pressure-sensitive adhesive composition.

When an adhesive sheet for protecting a coating film surface of an automobile or the like is produced by an extrusion method, a styrene elastomer is often used.
Patent Document 1 discloses a pressure-sensitive adhesive composition mainly composed of a copolymer obtained by hydrogenating a mixture of polymers composed of a styrene polymer block and a conjugated diene polymer block from the viewpoint of processability.
Patent Document 2 discloses an adhesive in which a hydrogenated random copolymer of styrene (1 to 50% by weight) -diene hydrocarbon (99 to 50% by weight) and an amorphous polypropylene elastomer are blended at a specific ratio. An agent composition is disclosed.
Patent Document 3 includes a hydrogenated product of an amorphous olefin copolymer, a crystalline olefin polymer, and a styrene block copolymer in a specific ratio, and a tan δ at 10 HZ is 0.2 or more and 1.0. An adhesive composition that is less than is disclosed.
Patent Document 4 discloses a surface protective film including an adhesive layer containing a vinyl isoprene block and having a specific adhesive layer hardness (Martens hardness).
Patent Document 5 discloses a pressure-sensitive adhesive composition in which a hydrogenated product of a triblock copolymer in which a polystyrene block and a vinyl-isoprene block are combined and an amorphous polypropylene elastomer are blended at a specific ratio.

Japanese Patent Publication No. 5-74627 Japanese Patent No. 4275191 JP 2006-188646 A JP 2010-126711 A International Publication No. 2013/011561

  However, a phenomenon in which the adhesive force increases with time is often observed with the styrene-based adhesive, but this impairs the re-peeling performance, which is one of the functions of the protective sheet. In addition, since it is assumed that the protective sheet is used in various environments, it is necessary to show adhesiveness in a wide temperature range, and after peeling, abnormalities such as adhesive residue on the adherend and paint film marks Not desirable.

In order to solve these problems, for example, Patent Document 5 proposes a pressure-sensitive adhesive composition in which an olefin copolymer is blended with a hydrogenated styrene elastomer.
However, the conventional pressure-sensitive adhesive composition for a protective sheet has used a hydrogenated styrene elastomer or olefin copolymer having a high glass transition point (Tg) in order to obtain heat resistance. In order to make it suitable, it was necessary to mix | blend a softener etc. in large quantities. As a result, it has been difficult for the conventional pressure-sensitive adhesive composition for a protective sheet to achieve both low-temperature characteristics and suppression of adhesion enhancement.

  The present invention is a novel coating film protection that exhibits good adhesive properties in a wide temperature range from low temperature to high temperature, while having no increase in adhesive strength over time, and suppressing residual adhesive and coating marks after peeling. It aims at providing an adhesive composition.

As a result of intensive studies to achieve the above object, the present inventors have completed the present invention.
That is, the present invention relates to a pressure-sensitive adhesive composition having a loss tangent tan δ at 0 to 100 ° C. of 0.6 or less and a storage elastic modulus G ′ at 0 to 100 ° C. of 100,000 Pa or more. .

The adhesive composition of the present invention exhibits adhesiveness in a wide temperature range from low temperature to high temperature, while there is no increase in adhesive strength over time, and adhesive residue and coating film marks after peeling are suppressed, and good removability Also shown.
Further, in the pressure-sensitive adhesive composition of the present invention, the blending amount of the softening agent is set to an appropriate range, for example, component I to be described later and the like so as not to drip at high temperature and not to increase adhesive strength. It can also be contained in 15-30 mass parts with respect to 100 mass parts in total with the component II or 100 mass parts in total with the component A and the component B mentioned later.

It is a figure which shows the temperature dispersion | variation of the loss tangent tan-delta of Example 1, storage elastic modulus G ', and loss elastic modulus G' '. It is a figure which shows the temperature dispersion | variation of the loss tangent tan-delta of Example 2, storage elastic modulus G ', and loss elastic modulus G' '. It is a figure which shows the temperature dispersion | variation of the loss tangent tan-delta of Example 3, storage elastic modulus G ', and loss elastic modulus G' '. It is a figure which shows the temperature dispersion | variation of the loss tangent tan-delta of Example 4, storage elastic modulus G ', and loss elastic modulus G' '. It is a figure which shows the temperature dispersion | variation of the loss tangent tan-delta of Comparative Example 1, the storage elastic modulus G ', and the loss elastic modulus G ". It is a figure which shows the temperature dispersion | variation of the loss tangent tan-delta, the storage elastic modulus G ', and the loss elastic modulus G "of the comparative example 2.

[Adhesive composition]
Since the pressure-sensitive adhesive composition of the present invention exhibits adhesiveness in a wide temperature range from low temperature to high temperature, the loss tangent tan δ at 0 to 100 ° C. is 0.6 or less, preferably 0.55 or less. Further, the lower limit value of the loss tangent tan δ is not particularly limited, but may be, for example, 0.1 or more.
The pressure-sensitive adhesive composition of the present invention also has a storage elastic modulus G ′ at 0 to 100 ° C. of 100,000 Pa or more, preferably 150,000 Pa or more, in order to increase cohesion and obtain good removability. Preferably, it is 200,000 Pa or more. The upper limit value of the storage elastic modulus G ′ is not particularly limited, but is, for example, 1,000,000 Pa or less.
The tan δ and the storage elastic modulus G ′ of the pressure-sensitive adhesive composition are measured by the methods described in the examples.

  The pressure-sensitive adhesive composition can be obtained by using, for example, a low Tg elastomer instead of a conventional high Tg elastomer. For example, the low Tg is preferably −5 ° C. or lower, more preferably −9 ° C. or lower, and further preferably −15 ° C. or lower. In this case, not only an adhesive composition having excellent extrudability and heat resistance can be obtained, but also the addition amount of the softening agent can be suppressed, so that an increase in adhesion can be suppressed. The elastomer is not particularly limited as long as Tg is low, and specific examples thereof include styrene elastomers and amorphous polyolefin elastomers.

In particular, the adhesive composition includes a low Tg elastomer (component I) having a heat-resistant hard segment (crystal part), and a low Tg elastomer having no clear crystal domain and excellent extrudability ( It can be obtained using component II).
The heat-resistant hard segment (crystal part) in the above component I refers to a material that has a glass transition point (Tg) higher than room temperature and collapses when heated to Tg or more, and is plasticized. Examples include styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, pt-butylstyrene, 2,4-dimethylstyrene, divinylstyrene, 1,1-diphenylstyrene vinylnaphthalene, vinylanthracene, and the like. . The component I is not particularly limited as long as it has the above heat-resistant hard segment, and examples thereof include SEBS, SEPS, SEEPS, HSBR and the like.
Component II is not particularly limited as long as it has an amorphous structure, and examples thereof include amorphous polyolefin and butyl rubber.
The glass transition points Tg of component I and component II may be the same or different, and a low Tg is preferable. For example, a pressure-sensitive adhesive composition having good heat resistance can be obtained, and a melt index. In view of increasing the productivity by coextrusion while keeping (MI) low, it is preferably −5 ° C. or lower, more preferably −9 ° C. or lower, and further preferably −15 ° C. or lower.

  The pressure-sensitive adhesive composition may contain a styrene elastomer (component A) and an amorphous polyolefin elastomer (component B).

The styrene elastomer (component A) used in the pressure-sensitive adhesive composition of the present invention is not particularly limited, and a known styrene elastomer can be used. Styrenic block copolymers are preferred, hydrogenated styrene block copolymers are more preferred, and polystyrene-poly (ethylene-ethylene / propylene) block-polystyrene block copolymers (SEEPS) are more preferred.
Examples of commercially available styrenic elastomers that can be used for the component A include, but are not limited to, Hybra (registered trademark) manufactured by Kuraray Co., Ltd.

The amorphous polyolefin elastomer (component B) used in the pressure-sensitive adhesive composition of the present invention has an increased adhesion of the resulting pressure-sensitive adhesive composition compared to a crystalline polyolefin elastomer such as non-amorphous Vistamaxx (registered trademark). This is advantageous in that it is suppressed.
The amorphous polyolefin elastomer is not particularly limited, and a known amorphous polyolefin elastomer can be used, and an amorphous polypropylene elastomer, particularly an amorphous propylene-α olefin copolymer elastomer (however, The α-olefin is preferably free of ethylene and propylene.
The “amorphous polyolefin elastomer” in the present invention means that (weight of crystal part) / (weight of the whole polymer) is 0.5 or less. Here, the weight of the crystal part can be determined from the crystallinity (mass fraction of the crystal part with respect to the total mass). This crystallinity can be determined from the X-ray diffraction pattern of the polymer (S. Krimm, AV Tobolsky: J. Polymer Sci., 7, 57, 1951). Although not particularly limited as a product, the above (weight of crystal part) / (weight of the whole polymer) is preferably 0, for example, Tough Selenium X1102 manufactured by Sumitomo Chemical Co., Ltd.
Examples of commercially available amorphous polyolefin elastomers that can be used for Component B include, but are not limited to, Tufselen (registered trademark) manufactured by Sumitomo Chemical Co., Ltd.

  The glass transition point Tg of the component A and the component B may be the same or different, and a pressure-sensitive adhesive composition having good heat resistance can be obtained. From the viewpoint of improving productivity, the temperature is preferably −5 ° C. or lower, more preferably −9 ° C. or lower, and further preferably −15 ° C. or lower.

  Of the total 100 parts by mass of the component A and the component B, the component A is 51 parts by mass to 80 parts by mass, and the component B is 49 parts by mass from the viewpoint of suppressing the increase in adhesion of the obtained adhesive composition. The component A is preferably 60 parts by mass to 80 parts by mass, and the component B is more preferably 40 parts by mass to 20 parts by mass.

  As long as the effect of the present invention is not adversely affected, an elastomer other than the component A and the component B can be added to the pressure-sensitive adhesive composition of the present invention.

  In addition, the pressure-sensitive adhesive composition of the present invention includes a tackifier resin, a softening agent, a light-resistant stabilizer, an anti-aging agent or an antioxidant, a pigment, an inorganic filler, and an organic filler as long as the effects of the present invention are not adversely affected. Agents, antistatic agents, and other additives can be added.

The tackifier resin does not particularly limit the number of parts by mass in order to control the number of parts according to the target. However, in consideration of removability, storage elastic modulus, and low temperature tackiness, a total of 100 of component A and component B is considered. 5-50 mass parts and 5-35 mass parts are more preferable with respect to mass parts.
The tackifying resin is not particularly limited, and rosin tackifying resin, terpene tackifying resin, coumarone / indene tackifying resin, styrene resin, aliphatic or alicyclic or aromatic petroleum resin, and those A known tackifying resin such as a hydrogenated product can be used.

The softener does not particularly limit the number of parts by mass in order to control the number of parts according to the target. However, in consideration of removability, storage elastic modulus, and low-temperature adhesiveness, the total of the component A and the component B is 100 masses. 10-30 mass parts is more preferable with respect to the part.
As the softener, one or more known softeners can be used. However, in the case where a sticky softener is used, a softener having no stickiness such as process oil is 50% by mass or more in the total softener. It is preferable to blend.
In the present invention, when an elastomer having a lower Tg than that conventionally used is used, an appropriate softener is selected in order to solve the heat resistance problem, and the blending amount thereof is the conventional one. It is preferable to reduce more. In addition, when the compounding quantity of a softening agent is reduced, enhancement of adhesive force will increase easily.

  The anti-aging agent is not particularly limited in order to control the number of parts according to the target, but is 0.5 to 5 parts by mass with respect to 100 parts by mass in total of the component A and the component B. preferable.

[Adhesive sheet]
The pressure-sensitive adhesive sheet of the present invention contains the above-mentioned pressure-sensitive adhesive composition, and has, for example, at least one side of the substrate.

  The substrate of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and a film, a nonwoven fabric, a woven fabric, or paper can be used, but from the viewpoint of adhesive sheet workability, durability, and cost, preferable. The film material is preferably a thermoplastic resin from the viewpoint of processability, more preferably a polyolefin-based thermoplastic resin, and further preferably a polypropylene-based thermoplastic resin or a polyethylene-based thermoplastic resin from the viewpoint of cost.

  The base material of the pressure-sensitive adhesive sheet of the present invention can be a single layer or two or more layers.

  The base material of the pressure-sensitive adhesive sheet of the present invention comprises a long-chain alkyl release agent, silicone on the surface opposite to the surface having the pressure-sensitive adhesive composition in order to lighten the unraveling of the pressure-sensitive adhesive sheet rolled up. A known release agent such as a system release agent may be coated. Moreover, you may mix | blend or coat a well-known antiblocking agent with a base material.

  Although the thickness of the base material layer of the adhesive sheet of this invention is not specifically limited, From a viewpoint of workability | operativity or cost, 20-80 micrometers is preferable, and 30-70 micrometers is more preferable.

  The thickness of the pressure-sensitive adhesive composition layer of the pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 5 to 20 μm from the viewpoint of workability and cost.

The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and a known method can be used. However, it is preferable to prepare the pressure-sensitive adhesive sheet by hot melt coating (hot melt coating). However, the present invention is not limited to this. For example, if the pressure-sensitive adhesive composition is soluble in a solvent, it may be prepared by a spread coating method.
Moreover, when the base material of the adhesive sheet | seat of this invention is a thermoplastic resin, it can also coextrude with an adhesive composition.

  Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited thereto. In the following examples and comparative examples, parts and% indicate, in principle, parts by mass and% by weight, respectively.

〔material〕
Component A: Hybler 7311, manufactured by Kuraray Co., Ltd., SEEPS, styrene polymer block-isoprene polymer block-vinyl isoprene polymer block-1,3-butadiene polymer block-vinyl 1,3-butadiene polymer block Copolymer hydrogenation, Tg = −32 ° C .;
Component B1: Tafthren X1102, Sumitomo Chemical Co., Ltd., amorphous polypropylene elastomer, Tg = -9 ° C.;
Component B2: Tafthren X1104, Sumitomo Chemical Co., Ltd., amorphous polypropylene elastomer, Tg = -24 ° C.;
Tackifying resin: Clearon K100, Yasuhara Chemical Co., Ltd., aromatic hydrogenated terpene resin;
Softener 1: Nippon Oil Polybutene HV300, JX Nippon Oil & Energy Corporation, Polybutene;
Softener 2: Diana Process Oil PW-150, Idemitsu Kosan Co., Ltd., paraffin oil;
Light-resistant stabilizer: Tinuvin 326, BASF, benzotriazole ultraviolet absorber;
Antioxidant: Antage W500, Kawaguchi Chemical Co., Ltd., phenolic antioxidant;

Example 1
Component A: Hybra 7311 70 parts by weight Component B2: Tough selenium X1104 30 parts by weight Tackifying resin: Clearon K100 15 parts by weight Softener 1: Nisseki Polybutene HV300 11.25 parts by weight Softener 2: Diana Process Oil PW-150 25 parts by weight Light-resistant stabilizer: Tinuvin 326 1 part by weight Antioxidant: Antage W500 0.6 parts by weight

[Preparation of samples for viscoelasticity measurement]
The composition having the above composition was molded into a sheet having a thickness of 1 mm using a 10 ton tabletop test press (Gonno Hydraulic Machinery Co., Ltd.) under the conditions of 160 ° C. and pressure of 40 kgf / cm ² . This was used as a sample for viscoelasticity measurement.
[Preparation of adhesive property measurement samples and tensile test samples]
3 kg of the pressure-sensitive adhesive composition having the above composition was previously kneaded at 180 ° C. and 200 rpm using a twin-screw extruder (product name TEM-35BH, Toshiba Machine Co., Ltd.), and the pressure-sensitive adhesive composition layer (thickness) 10 μm), together with a polypropylene base layer (thickness 40 μm), a 30 mmφ T die extruder is used to perform molding by melt coextrusion at a T die temperature of 210 ° C. and a film take-off speed of 5 m / min. Created a sheet. This pressure-sensitive adhesive sheet was cut into a 25 mm width tape to obtain a sample for measuring adhesive properties and a sample for tensile testing.

Example 2
Component A: Hiblar 7311 65 parts by weight Component B2: Tough selenium X1104 35 parts by weight Tackifying resin: Clearon K100 15 parts by weight Softener 1: Nisseki Polybutene HV300 11.25 parts by weight Softener 2: Diana Process Oil PW-150 25 parts by weight Light-resistant stabilizer: Tinuvin 326 1 part by weight Antioxidant: Antage W500 0.6 parts by weight

  A sample for measurement was prepared in the same manner as in Example 1 except that component A and component B2 were changed to the above composition and the proportion of component B2 was increased.

Example 3
Component A: Hiblar 7311 70 parts by weight Component B2: Tough selenium X1104 30 parts by weight Tackifying resin: Clearon K100 15 parts by weight Softener 1: Nisseki Polybutene HV300 10 parts by weight Softener 2: Diana Process Oil PW-150 10 parts by weight Light resistance Stabilizer: Tinuvin 326 1 part by weight Antioxidant: Antage W500 0.6 part by weight

  A measurement sample was prepared in the same manner as in Example 1 except that the mass parts of the tackifying resin and the softening agent were changed to the above composition and the softening agent was slightly reduced.

Example 4
Component A: Hybler 7311 70 parts by weight Component B2: Tough selenium X1104 30 parts by weight Tackifying resin: Clearon K100 15 parts by weight Softener 1: Nisseki Polybutene HV300 12.5 parts by weight Softener 2: Diana Process Oil PW-150 12. 5 parts by weight Light-resistant stabilizer: Tinuvin 326 1 part by weight Antioxidant: Antage W500 0.6 parts by weight

  A measurement sample was prepared in the same manner as in Example 1 except that the mass parts of the tackifying resin and the softening agent were changed to the above composition and the tackifying resin and the softening agent were slightly increased.

Comparative Example 1
Component A: 75 parts by weight of Hibler 7311 Component B1: 25 parts by weight of Tough Selenium X1102 Tackifying resin: 15 parts by weight of Clearon K100 Softener 1: 33 parts by weight of Nisseki Polybutene HV300 Light stabilizer: 1 part by weight of Tinuvin 326 Antioxidant: Antage W500 0.6 parts by mass

  Example 1 except that component B1 has a higher Tg, the mass parts of the tackifier resin and softener are changed to the above composition, the tackifier resin is slightly increased, and the softener is only polybutene and the mass part is increased. A measurement sample was prepared in the same manner.

Comparative Example 2
Component A: 75 parts by weight of Hibler 7311 Component B1: 25 parts by weight of Tough selenium X1102 25 parts by weight of tackifier resin: Clearon K100 25 parts by weight Softener 1: 33 parts by weight of Nisseki polybutene HV300 Light stabilizer: Tinuvin 326 1 part by weight Antioxidant: Antage W500 0.6 parts by mass

  A measurement sample was prepared in the same manner as in Comparative Example 1 except that the tackifying resin was slightly increased.

(Viscoelasticity measurement method)
Using a viscoelasticity measuring device (product name: Phyca MCR301, manufactured by Anton Paar), the sample was measured at a frequency of 1 Hz, a swing angle γ = 0.05%, a measurement temperature of −40 ° C. to 100 ° C. (measured from the low temperature side), and a temperature rise. The loss tangent tan δ, storage elastic modulus G ′, and loss elastic modulus G ″ of the pressure-sensitive adhesive composition were measured at a rate of 5 ° C./min. The results are shown in FIGS.

[Measurement method of adhesive properties]
As adhesive properties, adhesive strength, adhesive strength against coating film, post-aging adhesive strength against coating film, and 5 ° C. adhesive strength against coating film were measured by the following methods. The results are shown in Table 1.

Adhesive strength measurement method:
The sample adhesive strength was measured in accordance with JIS Z0237 2000 by measuring 180 ° peel force. In other words, a 25 mm wide sample was affixed to a BA SUS plate, reciprocated once with a 2 kg pressure roller, left in an atmosphere at 23 ° C. for 30 minutes, and then a 180 ° peel force was measured at a tensile speed of 0.3 m / min. did.

Method for measuring adhesion to coating film:
For the measurement of the adhesion of the sample to the coating film, a 180 ° peel force was measured in accordance with JIS Z0237 2000. That is, a 25 mm wide sample was attached to the coated plate, and after one round trip with a 2 kg pressure roller, it was left in a 23 ° C. atmosphere for 30 minutes, and then the 180 ° peel force was measured at a tensile speed of 0.3 m / min. .

Method for measuring adhesion to coating film after time:
For the measurement of the adhesion of the sample to the coating film over time, 180 ° peel force was measured according to JIS Z0237 2000. That is, a 25 mm wide sample was attached to the coated plate, and after one round trip with a 2 kg pressure roller, it was left in a 70 ° C. atmosphere for 9 days, and then a 180 ° peel force was measured at a pulling speed of 0.3 m / min. .

5 ° C. vs. coating film adhesion measurement method:
The 5 ° C. coating film adhesive strength measurement of the sample was based on JIS Z0237 2000, and the 180 ° peel force was measured. That is, a 25 mm wide sample was pasted on a coated plate, reciprocated once with a 2 kg pressure roller, left in a 5 ° C. atmosphere for 5 hours, and then 180 ° C. in a 5 ° C. atmosphere at a pulling speed of 0.3 m / min. ° Peel force was measured.

[Tensile test]
As a tensile test, the upper yield point load, 5% tensile load, 10% tensile load, elongation at break, and load at break were measured by conventional methods such as JIS. The results are shown in Table 1.

As shown in Table 1 and FIGS. 1 to 4, in Examples 1 to 4, tan δ at 0 ° C. to 100 ° C. is in the range of 0.6 or less, and the storage elastic modulus G ′ at 0 ° C. to 100 ° C. is 100, It was 000 Pa or more, there was little increase in adhesive strength, good removability, good adhesive residue and coating marks, and high adhesive strength at 5 ° C.
On the other hand, in Comparative Examples 1 and 2, tan δ of the pressure-sensitive adhesive composition at 0 ° C. to 100 ° C. exceeds 0.6, and the adhesive residue and the coating mark are good. It progressed compared with the Example, and the adhesive force in 5 degreeC was also significantly low compared with the Example.

  The pressure-sensitive adhesive composition of the present invention can be used for a pressure-sensitive adhesive sheet for protecting a coating film surface of a vehicle such as an automobile.

Claims (5)

Loss tangent tanδ at 0 to 100 ° C. is 0.6 or less, and Ri der storage modulus G 'is more than 100,000Pa at 0 to 100 ° C.,
A styrene-based elastomer (component A) having a glass transition point Tg of −5 ° C. or less;
An amorphous polyolefin elastomer (component B) having a glass transition point Tg of −5 ° C. or less;
A pressure-sensitive adhesive composition comprising: Of a total of 100 parts by weight of component A to component B, the component A and 51 parts by 80 weight parts, the component B and containing 49 parts by mass to 20 parts by weight, claim 1 adhesive composition. Adhesive sheet comprising a pressure-sensitive adhesive composition according to claim 1 or 2. The pressure-sensitive adhesive sheet according to claim 3 , which is used for protecting a coating film surface. The pressure-sensitive adhesive sheet according to claim 3 , which is used for protecting a coating film surface for a vehicle.

Images