JP2008239768A - Resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition which has excellent adhesion force not only with polar resins such as acrylic resins but also with polyolefin resins in particular without using a chlorine-containing compound and is suitable for primers and adhesives and the like. <P>SOLUTION: The resin composition comprises a polymer (A) having a (meth)acrylate monomer (a) unit in which an alicyclic hydrocarbon group is combined with an acryloyloxy group or a methacryloyloxy roup and a tackifier resin (B). The alicyclic hydrocarbon group is preferably a 4-t-butyl cyclohexyl group, and the tackifier resin (B) is preferably a rosin-based resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is, for example, a primer resin composition used as an undercoat of a paint or an adhesive used for bonding a substrate made of a polyolefin resin when coating a substrate made of a polyolefin resin. The present invention relates to a resin composition suitable as a resin composition for use.

Polyolefin resins are widely used in various applications because of their excellent mechanical properties and chemical resistance, as well as excellent moldability and recyclability. However, their low polarity makes it difficult to paint or bond. is there.
Therefore, when coating or adhering to polyolefin resin, the surface of polyolefin resin molding is activated by applying surface treatment such as plasma treatment, flame treatment, ultraviolet irradiation treatment, chromic acid treatment, etc. There is a known method for improving adhesion. However, performing such a surface treatment has problems that the process becomes complicated and a large amount of equipment costs are required.

Therefore, as a method of performing coating or adhesion without performing surface treatment, it has been proposed to use a chlorinated polyolefin resin having a strong adhesion to a polyolefin resin as a primer or an adhesive (for example, Patent Document 1). reference.). However, chlorinated polyolefin resin exhibits excellent adhesion to polar resins such as acrylic resins and is useful, but it contains chlorine, so it has become a concern for recent environmental problems. Its use tends to be avoided.
Then, the (meth) acrylic acid ester type polymer which has a specific structure as what does not contain chlorine is proposed. (See Patent Document 2).
JP-A-6-306227 International Publication No. 2004/018575 Pamphlet

  However, if the (meth) acrylic acid ester polymer described in Patent Document 2 is used, strong adhesion can be obtained for both polyolefin resin and polar resin. Further improvement of adhesion is desired.

  The object of the present invention is to provide excellent adhesion to not only polar resins such as acrylic resins but also polyolefin resins, without using chlorine-containing compounds, and is suitable for use as primers and adhesives. Is to provide a simple resin composition.

As a result of intensive investigations in view of the present situation, the present inventors have added a specific resin as an additive to a (meth) acrylic acid ester polymer having a specific structure, thereby adding to the polyolefin resin. The inventor has obtained knowledge that the adhesion can be improved, and has completed the present invention.
That is, the resin composition of the present invention comprises a polymer (A) having a (meth) acrylic acid ester monomer (a) unit in which an alicyclic hydrocarbon group is bonded to an acryloyloxy group or a methacryloyloxy group, and an adhesive. It contains an imparting resin (B).
The alicyclic hydrocarbon group is preferably a 4-t-butylcyclohexyl group.
The tackifier resin (B) is preferably a rosin resin.

  According to the present invention, it has excellent adhesion to not only polar resins such as acrylic resins but also polyolefin resins without using chlorine-containing compounds, and is suitable for use as a primer or adhesive. A resin composition can be provided.

Hereinafter, the present invention will be described in detail.
The resin composition of the present invention contains a specific polymer (A) and a tackifier resin (B).
The polymer (A) is a (meth) acrylic acid ester monomer (a) in which an alicyclic hydrocarbon group is bonded to an acryloyloxy group or a methacryloyloxy group (hereinafter sometimes referred to simply as a monomer (a)). .) A polymer having a unit as a constituent unit, and exhibits excellent adhesion not only to polar resins such as acrylic resins but also to polyolefin resins.

As the monomer (a) constituting the polymer (A), cyclohexyl (meth) acrylate, 4-t-butylcyclohexyl (meth) acrylate, 4-t-amylcyclohexyl (meth) acrylate, 3, 3, 5 -Trimethylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, cyclopentadienyl (meth) acrylate, etc. are mentioned. These can be used alone or in combination of two or more.
Among these, 4-t-butylcyclohexyl acrylate, in which the alicyclic hydrocarbon group is a 4-t-butylcyclohexyl group, is preferable in terms of better adhesion to polyolefin resins.

The polymer (A) may be a copolymer having other monomer (b) units different from the monomer (a) units as constituent units in addition to the monomer (a) units. . In that case, the polymer (A) may have any structure such as a random copolymer, a graft copolymer, or a block copolymer.
The monomer (b) is not particularly limited as long as it is a monomer different from the monomer (a) and can be copolymerized with the monomer (a). For example, methyl (meth) Linear and branched alkyl (meth) acrylates such as acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-hydroxyethyl (meth) Hydroxyl group-containing (meth) acrylates such as acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate, methacrylic acid, acrylic acid , Β-unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, maleic anhydride , Aromatic vinyl compounds such as styrene and α-methylstyrene, olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, cyclopentene, cycloheptene, norbornene; acetic acid And vinyl esters such as vinyl and vinyl balsatic acid. These can be used alone or in combination of two or more.

  The copolymerization ratio of the monomer (a) and the monomer (b) varies depending on the use, but from the viewpoint of adhesion to the polyolefin resin, the monomer (a ) Is preferably 50% by mass or more.

  In addition, the number average molecular weight of the polymer (A) is preferably 10,000 to 300,000, and more preferably 30,000 to 200,000 from the viewpoints of coatability, adhesive strength, and strength.

As a polymerization method of the polymer (A), known polymerization methods such as radical polymerization such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization, and anionic polymerization can be employed.
Although there is no restriction | limiting in particular in superposition | polymerization temperature, For example, superposition | polymerization can be performed at the temperature of 0-200 degreeC.
In order to adjust the molecular weight of the polymer, a chain transfer agent such as mercaptans can also be added.

When the polymer (A) is produced by radical polymerization, the radical polymerization initiator is not particularly limited. For example, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, t-butyl peroxide -Organic oxides such as 2-ethylhexanoate, lauroyl peroxide, t-butyl hydroperoxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethyl) And azo compounds such as valeronitrile). These radical polymerization initiators can be used alone or in combination of two or more.
The addition amount of the radical polymerization initiator is not particularly limited, but is generally in the range of 0.0001 to 10 parts by mass with respect to 100 parts by mass of the total amount of monomers used.

  As a method for recovering the polymer (A) as a solid after the production by solution polymerization, suspension polymerization or emulsion polymerization, a known method can be used. For example, in the case of producing by solution polymerization, a method of drying the solvent using a degassing extruder and a method of reprecipitation using a poor solvent such as methanol or hexane can be mentioned. In addition, in the case of producing by emulsion polymerization, a method of drying water by a spray drying method, a freeze drying method, or the like, a method of recovering a precipitate by salting out, or the like can be used.

The tackifier resin (B) contained in the resin composition of the present invention is to further improve the adhesion particularly to the polyolefin-based resin by using in combination with the polymer (A) described above, and specifically, Terpene resins such as rosin resins such as gum rosin, rosin modified maleic acid resin, rosin ester, terpene resins such as β-pinene polymer, and aromatic modified hydrogenated terpene resins.
Among these, rosin resins are preferable, and gum rosin and rosin-modified maleic resin are more preferable because they have a high effect of improving adhesion to polyolefin resins.

  The ratio of the polymer (A) and the tackifier resin (B) in the resin composition of the present invention is the mass ratio of the polymer (A) and the tackifier resin (B) (polymer (A) / tackifier resin). (B)) is preferably 60/40 to 99/1, more preferably 80/20 to 95/5. By making the mass ratio of the polymer (A) and the tackifier resin (B) in the above range, the adhesion to the polyolefin resin is more excellent.

  In addition, the resin composition of the present invention may include various stabilizers such as antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, and colorants such as inorganic pigments, organic pigments, dyes, etc., if necessary. Additives such as inorganic fillers, lubricants, and plasticizers can be blended.

Although there is no restriction | limiting in particular as a manufacturing method of the resin composition of this invention, For example, a polymer (A), tackifying resin (B), and the additive added as needed are heat-melt-mixed. Examples thereof include a method and a method in which an organic solvent is added to these and dissolved and mixed.
The method of heat-melt mixing is not particularly limited, and examples thereof include a melt-kneading method using a single screw extruder, a twin screw extruder, or the like.

As a method of dissolving and mixing an organic solvent, a known method may be used, and it is not particularly limited, but in general, the polymer (A) and tackifying are carried out in a container equipped with a stirrer. A method of mixing and dissolving the resin (B), an additive added as necessary, and an organic solvent while stirring simultaneously with heating is employed.
Examples of the organic solvent include aromatic hydrocarbons such as toluene, xylene, Solvesso 100 (trade name, manufactured by Exxon Chemical), alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, methyl ethyl ketone, methyl isobutyl ketone cyclohexanone, and the like. Ketones, and esters such as ethyl acetate and n-butyl acetate. These organic solvents can be used alone or in combination of two or more.
In the case where the polymer (A) is produced by solution polymerization using these organic solvents, the organic solvent solution of the produced polymer (A) is added to the tackifier resin (B) as necessary. Accordingly, an additive may be added and mixed and dissolved to obtain an organic solvent solution of the resin composition.

  The method of using the resin composition of the present invention varies depending on the application, but when used as a primer for a resin base material or an adhesive, for example, a method of adhering the resin composition to the base material by hot melt Examples thereof include a method of applying a sheet after forming into a sheet shape by a heating press or the like, and further heating and fusing, and a method of dissolving in an organic solvent and coating the substrate and then drying by heating.

When bonding to a substrate with hot melt, or when heat-sealing after forming into a sheet, the temperature varies depending on the material and application of the substrate. For example, in the case of a polypropylene resin substrate, in order to suppress deformation Is preferably 140 ° C. or lower, and more preferably 120 ° C. or lower. Moreover, in order to obtain high adhesive force, 80 degreeC or more is preferable and 100 degreeC or more is more preferable.
The concentration of the resin composition of the present invention when used by dissolving in an organic solvent is not particularly limited, but when it is necessary to improve the coating property, it is preferably 50% by mass or less. . The heating and drying temperature after coating varies depending on the material and use of the base material. For example, in the case of a polypropylene resin base material, 140 ° C. or lower is preferable and 120 ° C. or lower is more preferable in order to suppress deformation. Moreover, in order to obtain high adhesive force, 60 degreeC or more is preferable and 80 degreeC or more is more preferable.

  Such a resin composition includes a polymer (A) having a (meth) acrylate monomer (a) unit in which an alicyclic hydrocarbon group is bonded to an acryloyloxy group or a methacryloyloxy group, and a tackifying resin. Since (B) is contained, not only polar resins, such as an acrylic resin, but especially the adhesive force with respect to polyolefin resin is exhibited. Therefore, as a resin composition for a primer of a resin base material or an adhesive, specifically, for a primer for painting on various molded products such as automotive parts, various food packaging films, sheets, etc. It is suitable as an adhesive for molded articles.

Hereinafter, the present invention will be described more specifically with reference to examples.
In the examples, “part” represents “part by mass”.

[Production Example] Production of Toluene Solution of Resin Composition The following component 1 was placed in a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet, and thermometer.
(Component 1)
Toluene 100 parts 4-t-butylcyclohexyl acrylate 100 parts 2,2-azobisisobutyronitrile 0.05 part Next, the temperature of the system was raised to 70 ° C. while maintaining the temperature at 70 ° C. with nitrogen substitution. The polymerization was completed by holding for 8 hours.
Subsequently, 100 parts of toluene was added to the polymerization solution and stirred to dissolve completely, and then poured into 2000 parts of methanol to precipitate the polymer, and the precipitate was filtered to obtain a white solid. This white solid was dried under reduced pressure at 60 ° C. for 24 hours to obtain a polymer A-1.
The number average molecular weight of the obtained polymer A-1 was 109000 (measured by GPC using polystyrene as a standard sample).

[Example 1]
95 parts of the polymer A-1 obtained in the above production example and 5 parts of gum rosin [Arakawa Chemical Co., Ltd., China Rosin WW (trade name)] as a tackifying resin B-1 were dissolved in 400 parts of toluene. Thus, a 20% by mass toluene solution of the resin composition was obtained.
And the adhesive force of the resin composition with respect to a polyolefin-type base material was evaluated by the following evaluation method (I) using the toluene solution of this resin composition.

(Evaluation method of adhesion of resin composition to polyolefin base material (I))
A commercially available polypropylene resin pellet [Novatec TX-1810A (trade name) manufactured by Nippon Polypropylene Co., Ltd.] was used with an IS-30 injection molding machine [manufactured by Toshiba Corporation], barrel temperature 190 ° C., mold temperature 55 ° C. A 12 mm × 130 mm × 3 mmt square bar was produced by injection molding under the conditions of
Next, the obtained square bars were cut into two pieces each having a length of ½, and then these two pieces of square bars 1 and 2 were overlapped as shown in FIG. In the figure, reference numeral 1 denotes an upper square bar, and reference numeral 2 denotes a lower square bar. At that time, a chlorinated polypropylene [Super Clone 892LS (trade name) manufactured by Nippon Paper Industries Co., Ltd.] diluted with toluene to 50% by mass was used as an overlapping portion K (in the figure, It is shown as a dotted pattern).
Next, a glass plate is placed on the two square bars that have been superposed, and left at room temperature for 10 minutes under a pressure of 29 kPa, and then heated and bonded under the conditions of 80 ° C. × 1 hour to form a polyolefin-based substrate. Made the material.
Next, using the polyolefin base material thus obtained, as shown in FIG. 2, two pieces of the polyolefin base materials 3 and 4 were superposed in a cross so that the crossing angle thereof was substantially a right angle. In the figure, reference numeral 3 denotes an upper polyolefin base material, and reference numeral 4 denotes a lower polyolefin base material. At that time, about 20 mg of a 20% by weight toluene solution of the resin composition obtained as described above was used as an adhesive, the overlapping portion P of these two pieces of polyolefin-based substrates 3 and 4 (dotted pattern in the figure). It has been applied to.
Next, although not shown in the drawing, a glass plate is placed on these two polyolefin base materials stacked in a cross shape, and left at room temperature for 10 minutes under a pressure of 29 kPa, and then at 80 ° C. for 1 hour. The sample was heated and bonded under the conditions, and further allowed to stand in a constant temperature and humidity state of 23 ° C. and 50% humidity for 16 hours or more to prepare a cross-shaped adhesion test piece.
Next, as shown in FIG. 3, both ends of the upper polyolefin-based substrate 3 were placed on the fixing jigs 5 and 5 in an environment of 23 ° C. × humidity of 50% for the cross-shaped adhesive test piece thus obtained. In the state, a downward (arrow direction) stress is applied to the lower polyolefin-based substrate 4 (peeling speed 2 mm / min), and the lower polyolefin-based substrate 4 and the upper polyolefin-based substrate 3 are The maximum stress at the time of peeling was measured. This maximum stress is shown in Table 1 as the adhesive force of the resin composition to the polyolefin-based substrate. In addition, Tensilon [Orientec Co., Ltd. UTM-1-2500 type | mold Tensilon] was used for the measurement of the maximum stress.

[Examples 2 to 4]
A 20 mass% toluene solution of the resin composition was obtained in the same manner as in Example 1 except that the blending amount of the polymer A-1 and the tackifier resin B-1 was changed as shown in Table 1. And the adhesive force of the resin composition with respect to the polyolefin-type base material was evaluated like Example 1 except having used this. The results are shown in Table 1.

[Example 5]
Example 1 was used except that “rosin-modified maleic resin [Marquide No. 1 (trade name) manufactured by Arakawa Chemical Co., Ltd.]” was used as tackifying resin B-2 instead of tackifying resin B-1. Similarly, a 20% by mass toluene solution of the resin composition was obtained. And the adhesive force of the resin composition with respect to the polyolefin-type base material was evaluated like Example 1 except having used this. The results are shown in Table 1.

[Examples 6 to 7]
A 20 mass% toluene solution of the resin composition was obtained in the same manner as in Example 5 except that the blending amount of the polymer A-1 and the tackifier resin B-2 was changed as shown in Table 1. And the adhesive force of the resin composition with respect to the polyolefin-type base material was evaluated like Example 5 except having used this. The results are shown in Table 1.

[Comparative Examples 1-3]
A 20 mass% toluene solution of the resin composition was obtained in the same manner as in Example 1 except that the blending amounts of the polymer A-1 and the tackifier resins B-1 and B-2 were changed as shown in Table 1. . And the adhesive force of the resin composition with respect to the polyolefin-type base material was evaluated like Example 1 except having used this. The results are shown in Table 1.

[Example 8]
Using a twin-screw extruder, the polymer A-1 and the tackifying resin B-1 were melt-kneaded in the blending amounts shown in Table 2 (cylinder temperature 200 ° C., die temperature 200 ° C.), and the resin composition Got. Next, this resin composition was melt-pressed under the conditions of 180 ° C. and 2 MPa using a press molding machine [MP-2FH type mini test press manufactured by Toyo Seiki Seisakusho Co., Ltd.] to produce a sheet having a thickness of 0.1 mm. And cut into 13 mm squares.
And the adhesive force of the resin composition with respect to a polyolefin-type base material was evaluated by the following evaluation method (II) using this sheet | seat.

(Evaluation Method for Adhesive Strength of Resin Composition to Polyolefin Base (II))
Instead of applying the toluene solution of the resin composition to the overlapping portion P of the two pieces of the polyolefin-based substrates 3 and 4, the 13 mm square sheet obtained as described above was placed, and after standing at room temperature Adhesion test pieces were produced in the same manner as in the evaluation method (I) except that the heating and bonding conditions were set to 100 ° C. × 1 hour or 140 ° C. × 1 hour instead of 80 ° C. × 1 hour.
And about this, the maximum stress was measured like evaluation method (I). This maximum stress is shown in Table 2 as the adhesive force of the resin composition to the polyolefin-based substrate.

[Examples 9 to 10, Comparative Example 4]
Except having changed the compounding quantity of polymer A-1 and tackifying resin B-1 and B-2 as shown in Table 2, it obtained resin composition like Example 8 and used this, and 13 mm A corner sheet was obtained.
And the adhesive force of the resin composition with respect to the polyolefin-type base material was evaluated like Example 8 except having used this sheet | seat. The results are shown in Table 2.

  As is clear from Tables 1 and 2, it was shown that the resin compositions of the examples have excellent adhesion to polyolefin resins and are suitable for primers and adhesives.

  The resin composition of the present invention has excellent adhesion to not only a polar resin such as an acrylic resin but also a polyolefin resin without using a chlorine-containing compound. Therefore, it can be widely used, for example, as a primer for coating various molded products such as automobile parts, and as an adhesive for various molded products such as food packaging films and sheets.

It is explanatory drawing of the polyolefin-type base material used when evaluating the adhesive force of the resin composition with respect to a polyolefin-type base material. It is explanatory drawing of the adhesion test piece used when evaluating the adhesive force of the resin composition with respect to a polyolefin-type base material. It is explanatory drawing explaining the method of measuring the maximum stress at the time of the lower polyolefin-type base material and the upper polyolefin-type base material peeling about the adhesion test piece of FIG.

Claims (3)

  A polymer (A) having a (meth) acrylic acid ester monomer (a) unit in which an alicyclic hydrocarbon group is bonded to an acryloyloxy group or a methacryloyloxy group, and a tackifying resin (B) A resin composition characterized by the above.   The resin composition according to claim 1, wherein the alicyclic hydrocarbon group is a 4-t-butylcyclohexyl group.   The resin composition according to claim 1 or 2, wherein the tackifying resin (B) is a rosin resin.

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