JP2011021201A - Adhesive composition and adhesive product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition which does not cause an environmental problem and can exhibit good adhesive strength and holding characteristics within a wide temperature range from an ultra-low temperature to a high temperature. <P>SOLUTION: The adhesive composition comprises a random copolymer comprising isobutylene and paramethylstyrene, wherein the random copolymer contains 1-20 wt.% of the paramethylstyrene and has a crosslinked structure, and a tackifier. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive product using the same. The pressure-sensitive adhesive product of the present invention can be advantageously used, for example, when a rubber automobile part is attached to a predetermined part of the automobile.

  As is well known, a rubber part, for example, a so-called “weather strip”, is used to prevent the inside of a vehicle and other vehicles, for example, a peripheral portion of a door portion from being affected by wind and rain and dust, and to serve as a soundproofing material. Is attached. Usually, a weather strip is formed from a terpolymer (EPDM) composed of three components of ethylene, propylene and diene from the viewpoint of obtaining excellent flexibility, oxidation resistance and aging resistance.

  In general, when a weather strip made of EPDM is attached to a predetermined part of a vehicle such as an automobile, mechanical fixing means such as clip fastening and channel fitting are used. This is because EPDM is generally a poorly adhesive material with low surface energy and is effective for attaching EPDM weatherstrips to vehicles despite the various types of adhesives that are commercially available. This is because there is no adhesive. For the same reason, the attachment of EPDM automobile parts other than weather strips and other EPDM members is also left to the use of mechanical fixing means. However, since the use of mechanical fixing means is accompanied by drawbacks such as complicated work and high costs, it is desirable to provide a fixing means that makes it possible to more easily attach EPDM or similar rubber parts. It is rare.

  In order to satisfy the above requirements, for example, an attempt has been made to use an adhesive tape having a heat-sealing layer on an adhesive layer. In this method, after the adhesiveness is expressed by heating the heat-sealable layer, the heat-sealable layer is attached to the EPDM weatherstrip as the adherend, and the adhesive layer is attached to a predetermined part of the automobile. That's it. However, heating of the heat-sealing layer of the pressure-sensitive adhesive tape generally requires a large-scale costly heating facility, and the attaching speed is slow.

  Further, although it is not intended to be used for attaching an EPDM weatherstrip to an automobile, Patent Document 1 discloses fluidity that can be directly adhered to EPDM, which is useful for a membrane roofing application. An adhesive composition is disclosed. This adhesive composition contains polychloroprene as a main component. However, since it is essential to use a solvent in combination with polychloroprene, this adhesive composition is not preferable particularly in the automobile production line from the viewpoint of the recent environmental protection in which no solvent is used.

  Furthermore, Patent Document 2 discloses a pressure-sensitive adhesive containing a block copolymer composed of a vinyl aromatic monomer, isobutylene and a vinyl aromatic monomer. This pressure-sensitive adhesive has a drawback that it is inferior in heat resistance because its main component is a block copolymer and it does not have crosslinking or the like. In particular, this pressure sensitive adhesive can only exhibit significantly lower adhesion under the relatively high temperature and harsh conditions to which the weatherstrip is exposed.

JP 7-268299 A JP 7-138447 A

  The object of the present invention is to solve various problems of the prior art as described above, and to adhere to an adherend having a low surface energy in a wide temperature range from a very low temperature to a high temperature. It is an object of the present invention to provide an improved pressure-sensitive adhesive composition that allows retention properties.

  Another object of the present invention is to provide a pressure-sensitive adhesive composition that is easy to handle and does not cause the problem of environmental pollution caused by the use of a solvent.

  An object of the present invention is to provide a pressure-sensitive adhesive composition that can be advantageously used particularly for mounting rubber parts, particularly EPDM parts, to vehicles such as automobiles.

  Still another object of the present invention is to provide a pressure-sensitive adhesive product using the pressure-sensitive adhesive composition as described above.

In one aspect of the present invention, a random copolymer comprising isobutylene and paramethylstyrene;
A tackifier,
An adhesive composition comprising:
The pressure-sensitive adhesive composition is characterized in that the random copolymer contains 1 to 20% by weight of the paramethylstyrene and has a crosslinked structure.
Moreover, this invention provides the adhesive product which uses the adhesive composition of this invention in the other surface.

As described below, according to the present invention, an adherend made of a plastic material such as a rubber such as EPDM or a polypropylene blended with rubber,
(1) In a wide temperature range from very low temperature to high temperature, it can show good adhesive strength and holding characteristics,
(2) It can adhere to the adherend with excellent weather resistance even under severe conditions such as high temperature,
(3) Does not cause environmental pollution problems,
An adhesive composition is provided. The pressure-sensitive adhesive composition of the present invention can be advantageously used particularly for attaching rubber or rubber compounded plastic products to vehicles such as automobiles.

  As will be described in detail below, the pressure-sensitive adhesive composition according to the present invention is represented by rubber such as EPDM as described above, and Toyota's TSOP (Toyota Super Olefin Plastic; Trademark) series. In addition, it has excellent adhesion to an adherend having a low surface energy not only at room temperature but also at high temperature.

  As described above, the pressure-sensitive adhesive composition of the present invention is a random polymer comprising isobutylene and paramethylstyrene, and the random copolymer contains 1 to 20% by weight of paramethylstyrene and has a crosslinked structure. It is characterized by having. More specifically, this copolymer basically has a structure in which a random copolymer of isobutylene and paramethylstyrene is crosslinked with a crosslinking agent from the viewpoint of heat resistance. This type of random copolymer is commercially available from Exxon Chemical as the EXXPRO series, for example, MDX90-10, MDX89-4 (product number), and the like. Further, the methyl group at the para position of the paramethylstyrene can be partially brominated to become a crosslinking point. Therefore, a crosslinked structure can be formed according to the method described in detail below. In particular, copolymer MDX90-10 is brominated with 1.2 mol% of paramethylstyrene contained in the copolymer in an amount of 7.5% by weight. MDX89-4 is brominated with 0.75 mol% of paramethylstyrene contained in the copolymer in an amount of 5 wt%. In addition, bromination of paramethylstyrene and random polymerization of isobutylene and paramethylstyrene for producing a random copolymer can all be carried out using techniques common in the field of polymer chemistry. .

  In the random copolymer described above, the paramethylstyrene contained therein is not only characterized by forming the above-mentioned cross-linking points in order to induce excellent adhesion at room temperature to high temperature. Paramethylstyrene can give heat resistance and strength to the copolymer from its cohesive strength and hardness. In order to obtain such an effect, paramethylstyrene is contained in an amount of about 1 to 20 parts by weight based on the total amount of the copolymer in isobutylene and paramethylstyrene. Is preferred. Here, if the amount of paramethylstyrene is less than 1 part by weight, the cohesive force is insufficient, and it is difficult to obtain adhesiveness that can withstand practical use, particularly in a high temperature range. On the other hand, when the amount of paramethylstyrene exceeds 20 parts by weight, the flexibility is remarkably reduced, and stickiness, which is an important characteristic as an adhesive, disappears and can no longer be called an adhesive.

  The random copolymer used in the present invention preferably has a crosslinked structure in order to suppress a decrease in adhesiveness particularly at high temperatures. In fact, if it does not have a crosslinked structure, when the pressure-sensitive adhesive composition is exposed to high temperature conditions, the cohesive force becomes insufficient, and so-called adhesive residue is likely to occur. The crosslinking of the random copolymer can be basically performed using a technique such as vulcanization, as is generally performed in the field of polymer chemistry. However, in the case of vulcanization, a high reaction temperature and a long reaction time must be accepted. Therefore, in the present invention, as specifically employed in the following examples, cross-linking is performed using an amine-based cross-linking agent using a bromine atom that can be a cross-linking point in paramethylstyrene. preferable. Suitable crosslinking agents include, but are not limited to, triethylenetetramine (TETA), 4,4-trimethylenedipiperidine (TMDP), di-4-picolylamine, etc. Can do. The amount of such a crosslinking agent used can be widely varied depending on the type of crosslinking agent used. For example, when the crosslinking agent is TETA, it is preferably used in an amount of about 0.05 to 1 part by weight with respect to 100 parts by weight of the copolymer. When the amount of TETA is less than 0.05 parts by weight, cohesive failure of the adhesive tends to occur when the adhesive composition is used at a relatively high temperature such as 80 ° C. On the other hand, if the amount is more than 1 part by weight, the pressure-sensitive adhesive becomes too hard after crosslinking due to the increase in cohesive force, and the stickiness and flexibility required for the pressure-sensitive adhesive are lost.

  In the pressure-sensitive adhesive composition according to the present invention, a tackifier is contained in combination with the specific random copolymer as described above. Although various tackifiers generally known in this technical field can be arbitrarily used, in the practice of the present invention, in order to form a pressure-sensitive adhesive composition having excellent adhesive properties particularly at high temperatures, for example, Tackifiers such as those listed below can be advantageously used: hydrocarbon-based resins such as Regalrez 6108 (trade name) from Hercules; fully hydrogenated rosins such as Foral 105 from Hercules Product name), etc .; partially hydrogenated hydrocarbon resins such as MGB279 and MGB275 manufactured by Hercules (both are trade names). The amount of such tackifier used can be widely changed depending on factors such as the desired effect, but is usually about 50 to 150 parts by weight per 100 parts by weight of the copolymer. Is preferably used. If the amount of the tackifier is less than 50 parts by weight, the characteristics of rubber are strongly expressed, so that it cannot be a pressure-sensitive adhesive. On the other hand, when the amount is more than 150 parts by weight, only the characteristic of the tackifier becomes strong.

  The pressure-sensitive adhesive composition according to the present invention may contain other additives as necessary. For example, in order to improve adhesion at low temperatures and tack, a small amount of a plasticizer such as that commercially available as Shellflex SF-371JY (trade name) from Shell, for example, is preferably in an amount of 50 parts by weight or less. Therefore, it may be added to the pressure-sensitive adhesive composition.

  In addition, for the same purpose as the plasticizer described above, other flexible rubber components such as liquid isobutylene rubber commercially available as the Vistanex (trade name) series from Tonex, for example, Asaprene # 1205 (trade name) from Asahi Kasei. A commercially available styrene-butadiene rubber (SBR) having a relatively low glass transition temperature and the like may be added to the pressure-sensitive adhesive composition in a slight amount, preferably 50 parts by weight or less.

  The pressure-sensitive adhesive composition according to the present invention can be used to provide various pressure-sensitive adhesive products. Although the pressure-sensitive adhesive products according to the present invention can vary widely and are not limited to specific forms, typical examples of preferred pressure-sensitive adhesive products are pressure-sensitive adhesive compositions for fiber materials such as woven or non-woven fabrics. A pressure-sensitive adhesive composition is applied to a pressure-sensitive adhesive product coated or impregnated, a foam substrate such as acrylic foam, urethane foam, or polyethylene foam, or a plastic film such as polyester film or a substrate such as paper such as cellophane. Examples of the applied adhesive product include an adhesive tape, an adhesive sheet, an adhesive film, a foam tape, a transfer tape, and a double-sided tape.

  The pressure sensitive adhesive product of the present invention can be manufactured using various techniques known in the art. An example of a production method that can be advantageously used in the practice of the present invention is as follows. First, raw materials such as a selected random copolymer, tackifier, and plasticizer are dissolved in toluene or other solvent and applied. Prepare the solution. Next, the obtained coating solution is coated on a substrate such as a polyester film, and heated for a predetermined temperature and time, thereby removing the solvent by drying and crosslinking the copolymer. The desired pressure-sensitive adhesive product can be obtained through such a simple manufacturing method.

  According to another method, the pressure-sensitive adhesive product of the present invention can be produced by a hot melt method using an extruder.

  Furthermore, when the pressure-sensitive adhesive product of the present invention is affixed to an adherend after it is produced, it can also exhibit better adhesiveness by heating to an appropriate temperature.

  Subsequently, the present invention will be described according to its examples. It should be understood that the present invention is not limited to the following examples.

Example 1
As raw materials, the following rubbers and tackifiers were prepared in the amounts described.

Random copolymer of isobutylene and paramethylstyrene (EXXPRO MDX90-10, product number manufactured by Exxon Chemical Co., Ltd.) 100 parts by weight Tackifier (Regalrez 6108, product name of Hercules) 100 parts by weight

  These raw materials were dissolved in toluene to prepare a solution containing about 25% by weight of nonvolatile content. Furthermore, 0.12 part by weight of triethylenetetraamine (TETA) was added as a crosslinking agent to the obtained solution, and the mixture was sufficiently stirred. After stirring, the solution in which TETA was mixed was applied on a polyester film peel-treated with silicone so that the thickness after drying was 50 μm using a hand coater. Thereafter, the polyester film with the pressure-sensitive adhesive coating film was placed in an oven and heated at a temperature of 120 ° C. for 20 minutes to heat-dry the pressure-sensitive adhesive and perform a crosslinking reaction. The pressure-sensitive adhesive coating film was cured, and a transfer-type pressure-sensitive adhesive tape body was obtained.

  Next, on one side of the transfer type adhesive tape main body, a surface modifier containing an acrylic polymer and isocyanate as main components: JPM-790 (product number) manufactured by Sumitomo 3M Co. is applied in a coating film thickness of 2 to 5 μm, Heat in an oven at 70 ° C. for 5 minutes to dry. Thereafter, this transfer-type pressure-sensitive adhesive tape main body was laminated to the acrylic foam core at room temperature via the surface coated with the surface modifier. The acrylic foam core used here was prepared according to a typical tape production procedure described in US Pat. No. 4,415,615 assigned to Esmay et al., Preferably 50 to 100 parts by weight. A copolymer of a substituted or unsubstituted alkyl acrylate or methacrylate monomer and 0 to 50 parts by weight of a copolymerizable monoethylene-based substituted monomer, and the thickness thereof was 1.2 mm. Monomers that can be advantageously used to make such acrylic foam cores are disclosed in U.S. Reissue Pat. No. 24,906 to Urich. Through a series of manufacturing processes as described above, an acrylic foam tape as an adhesive product according to the present invention was obtained.

Examples 2-5
An acrylic foam tape was produced by repeating the procedure described in Example 1. In this example, the amount of TETA added as a crosslinking agent was changed from 0.12 parts by weight as follows.

Example 2 0.14 parts by weight Example 3 0.15 parts by weight Example 4 0.20 parts by weight Example 5 0.25 parts by weight

Example 6
An acrylic foam tape was prepared by repeating the procedure described in Example 1, but in this example, as a random copolymer of isobutylene and paramethylstyrene, instead of EXXPRO MDX90-10 manufactured by Exxon Chemical Co., Ltd. EXXPRO MDX89-4 (product number) was used in the same amount, and the amount of TETA added as a crosslinking agent was changed from 0.12 parts by weight to 0.14 parts by weight.

Example 7
An acrylic foam tape was produced by repeating the method described in Example 6. In this example, the amount of TETA added as a crosslinking agent was changed from 0.14 parts by weight to 0.16 parts by weight.

Example 8
An acrylic foam tape was produced by repeating the method described in Example 1, but in this example, the same amount of Foral 105 (trade name) manufactured by the same company was used instead of Hercules Regalrez 6108 as a tackifier. The amount of TETA added as a crosslinking agent was changed from 0.12 parts by weight to 0.14 parts by weight.

Example 9
An acrylic foam tape was prepared by repeating the procedure described in Example 1. In this example, when preparing a solution containing a random copolymer of isobutylene and paramethylstyrene and a tackifier, 10 parts by weight of a liquid was prepared. Isobutylene rubber: Vistanex LM-MS (trade name) manufactured by Tonex Co., Ltd. was further added, and the amount of TETA added as a crosslinking agent was changed from 0.12 parts by weight to 0.14 parts by weight.

Example 10
An acrylic foam tape was prepared by repeating the method described in Example 9, but in this example, the amount of liquid isobutylene rubber: Vistanex LM-MS added was changed from 10 parts by weight to 30 parts by weight.

Example 11
An acrylic foam tape was prepared by repeating the procedure described in Example 1. In this example, when preparing a solution containing a random copolymer of isobutylene and paramethylstyrene and a tackifier, 10 parts by weight of plastic was prepared. Agent: Shellflex SF-371JY (trade name) manufactured by Shell was further added, and 0.17 part by weight of 4,4-trimethylenedipiperidine (TMDP) was used as a crosslinking agent instead of TETA.

Example 12
Although the acrylic foam tape was produced by repeating the method described in Example 11, the addition amount of the plasticizer: Shellflex SF-371JY was changed from 10 parts by weight to 20 parts by weight.

Comparative Example 1
In this example, a commercially available acrylic foam tape, an acrylic foam tape # 5373 for low surface energy adherend manufactured by Sumitomo 3M Co., Ltd. was prepared for use in a comparative test.

Comparative Example 2
An acrylic foam tape was produced by repeating the method described in Example 1, but in this example, the use of the cross-linking agent: TETA was omitted in order to provide a comparative test.

Comparative Example 3
Although the acrylic foam tape was produced by repeating the method described in Example 6, in this example, the use of the cross-linking agent: TETA was omitted in order to provide a comparative test.

〔Evaluation test〕
Using the acrylic foam tape produced in each of Examples 1 to 12 and Comparative Examples 1 to 3 as a test tape, (1) adhesive strength, (2) heat resistance holding force, and (3) according to the following procedure The low temperature shear strength was evaluated.

(1) Adhesive strength The adhesive strength was evaluated by 180 ° peel test under different temperature conditions: normal temperature (about 25 ° C) and 80 ° C.

  As the adherend, three kinds of rubber members: EPDM (solid type and sponge type) manufactured by Hotta Rubber Co., Ltd. and TSOP-1 (trademark) manufactured by Toyota Co., Ltd. are prepared, and each test tape is provided at a predetermined site. Was pasted. The test tape used here is a slit-like tape obtained by backing the evaluation surface of the previously prepared tape with a polyester film having a thickness of 50 μm and then chopping it to a width of 12 mm. Next, in order to press-fit the test tape to the adherend, a roller having a weight of 2 kg was reciprocated on the tape. The test piece thus obtained was left at room temperature for 1 day, and then subjected to a 180 ° peel test using a tensile tester manufactured by Shimadzu Corporation. At this time, the pulling speed was 50 mm / min.

  Next, a 180 ° peel test at 80 ° C. was performed in the same manner as described above. However, after the test piece was left at room temperature for 1 day, the test was carried out by leaving the test piece in an atmosphere at a temperature of 80 ° C. for 30 minutes or longer.

  The results of the 180 ° peel test at room temperature and 80 ° C. are shown in Table 1 below. In Table 1, AT indicates that cohesive failure occurred in the adhesive.

(2) Heat resistant holding force As an adherend, a rubber member: EPDM (solid type, dimensions: about 30 mm × 70 mm × 5 mm) manufactured by Hotta Rubber Co., Ltd. was prepared. After the acrylic foam tape was cut into a size of 25 mm × 25 mm, the evaluation surface of the tape piece was fixed to a predetermined portion of the adherend, and the back surface of the evaluation surface was fixed to a stainless steel panel. . The obtained test piece was allowed to stand at room temperature for one day, and then placed in an oven at 90 ° C. so that the test piece was vertical, and the stainless steel panel side of the test piece was fixed to the oven. By applying a load of 1 kg to the adherend and reaching the limit of the heat-resistant holding force, the time (minutes) required for the adherend to fall off the test piece and to fall was measured. The obtained measurement results are shown in Table 1 below.

(3) Low temperature shear strength As an adherend, a rubber member: EPDM (solid type, dimensions: about 30 mm × 70 mm × 5 mm) manufactured by Hotta Rubber Co., Ltd. was prepared. After the acrylic foam tape is cut to a size of 25 mm × 10 mm, the evaluation surface of the tape piece is applied to a predetermined portion of the adherend, and the back surface of the evaluation surface is applied to a melamine alkyd resin paint coating plate. Attached and fixed. After leaving the obtained specimen at room temperature for one day, the shear strength (kg / cm ² ) of the specimen cooled to −30 ° C. for 1 hour or more with a tensile tester manufactured by Shimadzu Corporation having a cooling function is measured. did. At this time, the pulling speed was 2 mm / min. The obtained measurement results are shown in Table 1 below.

  As understood from the results shown in Table 1 above, the acrylic foam tapes produced in Examples 1 to 5 have excellent adhesive strength that can withstand practical use from low to high temperatures on adherends. ing. Further, as in Examples 6 and 7, even if the content ratio of paramethylstyrene in the copolymer as the main component is decreased to give flexibility to the pressure-sensitive adhesive, the acrylic foam tape still has excellent adhesive strength. be able to. Furthermore, even if the tackifier used in combination is changed as in Examples 8 to 12 or the rubber component or the plasticizer is additionally used, the acrylic foam tape still has excellent adhesive strength. be able to.

  On the other hand, in the acrylic foam tape using the general synthetic rubber transfer-type adhesive tape of Comparative Example 1, the adhesive strength significantly decreased at a high temperature, as is clear from the results shown in Table 1. Inevitable. Moreover, even if it contains the random copolymer which consists of isobutylene and paramethylstyrene as a main component, in the acrylic foam tape (Comparative Examples 2 and 3) in which the copolymer does not have a crosslinked structure, at high temperature, It was found that adhesive residue was generated in the adhesive layer of the transfer type adhesive tape. In particular, it was found that when the adherend is a sponge type EPDM, adhesive residue is generated even at room temperature. This is considered to be due to the influence of oil or the like that is a transition component from the EPDM side.

  Further, as understood from this fact, in the present invention, the copolymer constituting the pressure-sensitive adhesive is given a cross-linked structure such as a network structure. By doing so, the adhesive strength at high temperatures can be improved. It is possible to suppress a decrease and a decrease in cohesive force derived from the migration component.

Claims (2)

A random copolymer comprising isobutylene and paramethylstyrene;
A tackifier,
An adhesive composition comprising:
The pressure-sensitive adhesive composition, wherein the random copolymer contains 1 to 20% by weight of the paramethylstyrene and has a crosslinked structure.   A pressure-sensitive adhesive product comprising the pressure-sensitive adhesive composition according to claim 1.