JP7155580B2 - Composition, hot-melt pressure-sensitive adhesive composition and method for producing composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a composition capable of providing a hot-melt pressure-sensitive adhesive composition having excellent initial adhesive strength at low temperatures and having excellent moldability, workability and blocking resistance.

Since hot-melt adhesives harden in a short time, they can be used to efficiently adhere various products. It is an adhesive and is therefore used in various fields.

Hot-melt pressure-sensitive adhesives containing a styrene-based block copolymer as a base polymer and a tackifying resin are known.

In Patent Document 1, in the step of producing an adhesive using a styrene block copolymer as a base polymer, in the first kneading, the styrene block copolymer and a tackifying resin, which is one of the adhesive components, are mixed. Heated and kneaded in a separate device in advance, once cooled and solidified to be molded into small blocks or pellets, and then in a second kneading, the mixture of the first kneaded and the remaining adhesive components is fed into a compounding machine. A method for producing an adhesive is disclosed, which is characterized by charging and stirring and mixing.

According to Patent Document 1, although the productivity of the adhesive is improved, the initial adhesive strength at low temperatures, which is important when used as an adhesive, is insufficient.

Japanese Patent No. 3889341

The present invention has been made in view of such circumstances, and can provide a hot-melt pressure-sensitive adhesive composition having excellent initial adhesive strength at low temperatures, and excellent moldability, workability and blocking resistance. The purpose is to provide a composition that

The present inventors have conducted studies to achieve the above objects, and found that the tackifying resin contains a petroleum resin having a low softening point, the content of the block copolymer and the petroleum resin, and the glass transition temperature The present inventors have found that the above problems can be solved admirably by a composition in which is appropriately adjusted, and have completed the present invention.

That is, according to the present invention, there is provided a composition comprising a block copolymer having at least one aromatic vinyl polymer block and at least one conjugated diene polymer block, and a petroleum resin, the composition comprising a softening agent. The content of the block copolymer in the composition is in the range of 30 to 97% by mass, and the content of the petroleum resin in the composition is in the range of 3 to 70% by mass. and the softening point of the petroleum resin is 90°C or lower, and the composition has a glass transition temperature of less than 0°C as measured by dynamic viscoelasticity measurement.

The shape of the composition of the present invention is preferably pellet-like or crumb-like.
In the composition of the present invention, at least the block copolymer is selected from aromatic vinyl-conjugated diene block copolymers, aromatic vinyl-conjugated diene-aromatic vinyl block copolymers, and mixtures thereof. One type is preferred.
In the composition of the present invention, the content of the block copolymer in the composition is in the range of 50 to 90% by mass, and the content of the petroleum resin in the composition is 10 to 50% by mass. is preferably in the range of
In the composition of the present invention, the petroleum resin is at least one selected from the group consisting of aliphatic hydrocarbon resins, aliphatic-aromatic copolymer hydrocarbon resins, and hydrides thereof. is preferred.

In the composition of the present invention, the petroleum resin preferably has a softening point of 80° C. or lower.

Further, according to the present invention, there is provided a hot-melt pressure-sensitive adhesive composition containing the above composition and a plasticizer.

Further, according to the present invention, there is provided a method for producing the above composition, which comprises a step of kneading the block copolymer and the petroleum resin in a melted state.

ADVANTAGE OF THE INVENTION According to this invention, the hot-melt adhesive composition which is excellent in initial adhesive strength at low temperature can be provided, and the composition which is excellent in moldability, workability, and anti-blocking property can be provided.

(Composition)
The composition of the invention contains a block copolymer and a petroleum resin.

The block copolymer has at least one aromatic vinyl polymer block and at least one conjugated diene polymer block. The aromatic vinyl polymer block contains aromatic vinyl monomer units formed from aromatic vinyl monomers, and the conjugated diene polymer block comprises conjugated diene monomers formed from conjugated diene monomers. Contains units.

The aromatic vinyl monomer forming the aromatic vinyl monomer unit is not particularly limited as long as it is an aromatic vinyl compound. Examples include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4 -methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene , 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 4-bromostyrene, 2-methyl-4,6-dichlorostyrene, 2,4-dibromostyrene, vinylnaphthalene and the like. Among these, it is preferable to use styrene. These aromatic vinyl monomers can be used singly or in combination of two or more. Further, when the block copolymer has a plurality of aromatic vinyl polymer blocks, each aromatic vinyl polymer block may be composed of the same aromatic vinyl monomer units, or may be composed of different aromatic vinyl monomer units. It may be composed of vinyl monomer units.

In addition, the aromatic vinyl polymer block may contain other monomer units as long as the aromatic vinyl monomer unit is the main repeating unit. Examples of monomers constituting monomer units other than aromatic vinyl monomer units that can be contained in the aromatic vinyl polymer block include 1,3-butadiene, isoprene (2-methyl-1,3- butadiene), α,β-unsaturated nitrile monomers, unsaturated carboxylic acid or acid anhydride monomers, unsaturated carboxylic acid ester monomers, non-conjugated diene monomers, etc. mentioned. The content of monomer units other than aromatic vinyl monomer units in the aromatic vinyl polymer block is preferably 20% by mass or less, more preferably 10% by mass or less, and is substantially zero. % by weight is particularly preferred.

The conjugated diene monomer forming the conjugated diene monomer unit is not particularly limited as long as it is a conjugated diene compound. -chloro-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene and the like. Among these, 1,3-butadiene and/or isoprene are preferably used, and isoprene is particularly preferably used. By forming the conjugated diene polymer block from isoprene units, the obtained hot-melt pressure-sensitive adhesive composition can be made excellent in initial adhesive strength at low temperatures. These conjugated diene monomers can be used singly or in combination of two or more. Further, when the block copolymer has a plurality of conjugated diene polymer blocks, each conjugated diene polymer block may be composed of the same conjugated diene monomer units, or may be composed of different conjugated diene monomer units. It may be composed of units. Furthermore, hydrogenation reaction may be performed on a part of the unsaturated bonds of the conjugated diene polymer block.

In addition, the conjugated diene polymer block may contain other monomer units as long as the conjugated diene monomer unit is the main repeating unit. Examples of monomers constituting monomer units other than conjugated diene monomer units that can be contained in the conjugated diene polymer block include aromatic vinyl monomers such as styrene and α-methylstyrene, Examples include saturated nitrile monomers, unsaturated carboxylic acid or acid anhydride monomers, unsaturated carboxylic acid ester monomers, and non-conjugated diene monomers. The content of monomer units other than conjugated diene monomer units in the conjugated diene polymer block is preferably 20% by mass or less, more preferably 10% by mass or less, and substantially 0% by mass. is particularly preferred.

The vinyl bond content of the conjugated diene polymer block (ratio of 1,2-vinyl bond units and 3,4-vinyl bond units to all conjugated diene monomer units in the conjugated diene polymer block) is not particularly limited. However, it is preferably in the range of 1 to 20 mol %, more preferably in the range of 2 to 15 mol %, and particularly preferably in the range of 3 to 10 mol %.

If the block copolymer used in the present invention has at least one aromatic vinyl polymer block and at least one conjugated diene polymer block, the number of each polymer block and the bonding form thereof are It is not particularly limited. As a specific example of the form of the block copolymer used in the present invention, Ar represents an aromatic vinyl polymer block, D represents a conjugated diene polymer block, X represents a residue of a coupling agent, and n is an integer of 2 or more, an aromatic vinyl-conjugated diene block copolymer represented as Ar-D, an aromatic represented as Ar-D-Ar or (Ar-D) nX vinyl-conjugated diene-aromatic vinyl block copolymers, conjugated diene-aromatic vinyl-conjugated diene block copolymers represented as D-Ar-D or (D-Ar)nX, Ar-D- Aromatic vinyl-conjugated diene-aromatic vinyl-conjugated diene block copolymers represented by Ar-D, and mixtures of block copolymers obtained by mixing two or more of these in any combination may be mentioned. It can be, but is not limited to. Block copolymers particularly preferably used in the present invention include aromatic vinyl-conjugated diene block copolymers represented as Ar-D, and Ar-D-Ar or (Ar-D)nX. and block copolymers selected from aromatic vinyl-conjugated diene-aromatic vinyl block copolymers, as well as mixtures thereof.
Further, in the aromatic vinyl-conjugated diene-aromatic vinyl block copolymer represented as Ar-D-Ar or (Ar-D)nX, the molecular chain length of each aromatic vinyl block (Ar) is They may be the same or may contain different molecular chain lengths.

The weight average molecular weight of the block copolymer used in the present invention is not particularly limited, but is usually selected in the range of 40,000 to 500,000, preferably in the range of 50,000 to 400,000.

The content of the aromatic vinyl monomer unit in the block copolymer used in the present invention is not particularly limited, but is preferably in the range of 5 to 60% by mass, more preferably in the range of 7 to 55% by mass. , and more preferably in the range of 10 to 50% by mass. By setting the aromatic vinyl monomer unit content within the above range, the composition can be made more excellent in moldability, workability and blocking resistance, and the obtained hot-melt pressure-sensitive adhesive composition. can be favored by the initial tack at low temperatures. If the block copolymer is substantially composed of only the aromatic vinyl monomer unit and the conjugated diene monomer unit, Rubber Chem. Technol. , 45, 1295 (1972), the block copolymer is ozonolyzed and then reduced with lithium aluminum hydride to decompose the conjugated diene monomer unit portion to yield the aromatic monovinyl monomer. Since the unit portion can be taken out, the aromatic vinyl monomer unit content can be measured by such a method.

The melt index of the block copolymer used in the present invention is not particularly limited, but is preferably 0.1 to 1000 g/10 as a value measured according to ASTM D1238 (G condition, 200°C, 5 kg load). minutes, more preferably 0.1 to 100 g/10 minutes, still more preferably 0.5 to 40 g/10 minutes, particularly preferably 0.5 to 20 g/10 minutes Range. By setting the melt index within the above range, the moldability and workability of the composition can be made more excellent, and the resulting hot-melt adhesive composition has an initial adhesive strength at a low temperature and cohesion. It can be made superior by power. Moreover, by using a block copolymer having a particularly low melt index, the resulting hot-melt pressure-sensitive adhesive composition can have more excellent high-temperature properties.

A block copolymer comprising an aromatic vinyl polymer block and a conjugated diene polymer block as described above can be produced by a conventional method. By an anionic living polymerization method, an aromatic vinyl monomer and a conjugated diene monomer are sequentially polymerized to form a polymer block, and if necessary, a coupling agent is reacted to perform coupling. A method can be mentioned. A method of sequentially polymerizing an aromatic vinyl monomer, a conjugated diene monomer, and then an aromatic vinyl monomer to form a polymer block may also be used.

In addition, in the present invention, it is also possible to use a commercially available block copolymer. ), “Vector (registered trademark)” (manufactured by DEXCO Polymers), “Asaprene (registered trademark)”, “Tufprene (registered trademark)”, “Tuftec (registered trademark)” (manufactured by Asahi Kasei Chemicals), “Septon (registered trademark)” Trademark)” (manufactured by Kuraray Co., Ltd.) and the like can be used.

The content of the block copolymer in the composition of the present invention is in the range of 30 to 97% by mass, preferably in the range of 40 to 93% by mass, more preferably in the range of 50 to 90% by mass. . By setting the content of the block copolymer in the composition of the present invention within the above range, the moldability, processability and blocking resistance of the composition can be further improved, and the obtained hot-melt viscosity is The adhesive composition can be superior in initial tack at low temperatures.

The composition of the present invention contains petroleum resin. The type of petroleum resin is not particularly limited, but hydrocarbon resins are preferred, and among these, those classified as tackifying resins are particularly preferred. Examples thereof include aliphatic, aromatic, alicyclic or aliphatic-aromatic copolymer hydrocarbon resins and hydrides thereof. Among them, at least one selected from the group consisting of aliphatic hydrocarbon resins, aliphatic-aromatic copolymer hydrocarbon resins, and hydrides thereof is preferred.

The softening point of the petroleum resin is 90° C. or lower, preferably 85° C. or lower, more preferably 80° C. or lower, preferably 50° C. or higher, and more preferably 60° C. or higher. The softening point of petroleum resin is measured by the ring and ball method according to JIS K2207. Since the composition of the present invention contains a petroleum resin with a low softening point, for example, even if it contains a block copolymer with a low melt index, it has excellent moldability and processability. The hot-melt pressure-sensitive adhesive composition can be made superior in initial adhesive strength at low temperatures. Furthermore, petroleum resins having a low softening point tend to be inferior in blocking resistance, but the composition of the present invention, which contains a block copolymer, is also excellent in blocking resistance.

The weight average molecular weight of the petroleum resin is not particularly limited, but is usually in the range of 300-6000, preferably in the range of 500-5000.

The content of the petroleum resin in the composition of the present invention is in the range of 3-70% by mass, preferably in the range of 7-60% by mass, more preferably in the range of 10-50% by mass. By setting the content of the petroleum resin in the composition of the present invention within the above range, it is possible to make the composition more excellent in moldability, workability and blocking resistance, and the obtained hot melt adhesive The agent composition can be superior in initial tack at low temperatures.

A petroleum resin can be produced according to a conventional method. For example, it can be produced by addition polymerization of a monomer mixture using a Friedel-Crafts-type cationic polymerization catalyst. The method for preparing the monomer mixture is not particularly limited, and the desired monomer mixture may be obtained by mixing pure compounds, or the desired monomer mixture derived from, for example, a fraction of a naphtha decomposition product. A mixture containing monomers may be used to obtain the desired mixture of monomers. For example, in order to add 1,3-pentadiene or the like to the monomer mixture, the C5 fraction after extraction of isoprene and cyclopentadiene (including their multimers) can be suitably used.

The compositions of the present invention do not contain softeners. Since the composition of the present invention contains a petroleum resin with a low softening point, it is a hot-melt pressure-sensitive adhesive composition that has excellent workability and excellent initial adhesive strength at low temperatures, even though it does not contain a softening agent. can give Examples of softening agents include aromatic, paraffinic or naphthenic process oils, liquid polymers such as polybutene and polyisobutylene, which are added to ordinary hot-melt adhesive compositions. In the present specification, not containing a softening agent means that the content of the softening agent in the composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.1% by mass or less. , particularly preferably 0% by weight.

Since the composition of the present invention can provide a hot-melt pressure-sensitive adhesive composition which is superior in moldability, workability and blocking resistance and is superior in initial adhesive strength at low temperature, it is substantially block copolymerized. It is preferably composed only of coalesced and petroleum resins, more preferably composed only of block copolymers and petroleum resins.

The composition of the present invention may contain antioxidants, which are generally added to prevent deterioration of block copolymers and petroleum resins. The antioxidant is not particularly limited, and examples include pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3-(3,5-di-t -butyl-4-hydroxyphenyl)propionate, 2,6-di-t-butyl-p-cresol, hindered phenolic compounds such as di-t-butyl-4-methylphenol; Thiodicarboxylate esters; phosphites such as tris(nonylphenyl)phosphite; hindered amine light stabilizers (HALS); can be used. Although the amount of the antioxidant to be added is not particularly limited, it is usually 10 parts by weight or less, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the composition. In addition, antioxidant may be used individually by 1 type, and may be used in combination of 2 or more type.

The composition of the present invention can contain an anti-cohesion agent which is generally added to prevent blocking of block copolymers. The type of anti-adhesion agent is not particularly limited, but examples include powders of inorganic compounds such as silica, talc, calcium carbonate, and titanium oxide, powders of organic compounds such as calcium stearate, polyethylene, and polystyrene, and liquids such as silicone release agents. substances and the like. In order to obtain a high anti-blocking effect without deteriorating the performance of the adhesive composition, it is preferable to use an inorganic compound powder, and more preferably talc, silica, or the like can be used. The amount of mutual adhesion prevention agent added is not particularly limited, but from the viewpoint of exhibiting a sufficient anti-blocking effect and preventing dusting during handling, it is preferably 0.01 to 2.0% by mass in the composition. It is more preferably 0.05 to 1.0% by mass.

The glass transition temperature of the composition of the present invention is less than 0°C, preferably -2°C or less, more preferably -6°C or less, preferably -50°C or more, more preferably -30°C. °C or higher. By setting the glass transition temperature of the composition of the present invention within the above range, the blocking resistance of the composition can be made more excellent, and the obtained hot-melt pressure-sensitive adhesive composition can be used at a low temperature in the initial stage. It can be made excellent by adhesive strength. The glass transition temperature can be measured by dynamic viscoelasticity measurement, and when multiple peaks are observed, the peak derived from the conjugated diene polymer block is taken as the glass transition temperature of the composition of the present invention. . A peak derived from the conjugated diene polymer block is usually observed in a region on the lower temperature side than the peak of the aromatic vinyl polymer block.
In the composition of the present invention, it is preferable that the conjugated diene polymer block and the petroleum resin in the block copolymer are compatible with each other. The peak derived from the conjugated diene polymer block shifts to the higher temperature region due to compatibility with the petroleum resin.

The shape of the composition of the present invention is not particularly limited, and examples thereof include pellets, crumbs, bales, pillow packaging, and drum packaging. Among them, a pellet-like or crumb-like shape is preferable because it is excellent in handleability and is excellent in kneading easiness in producing a hot-melt pressure-sensitive adhesive composition. A pellet-like or crumb-like composition is obtained by molding a kneaded mixture of a block copolymer and a petroleum resin by a conventional method. Accordingly, the composition of the present invention may be a pellet-shaped or crumb-shaped molded article.

The composition of the present invention can be produced, for example, by a production method including a step of kneading the block copolymer and the petroleum resin in a melted state. In order to melt the block copolymer and the petroleum resin, the petroleum resin is usually heated to a temperature above its softening point, and the block copolymer is heated to a temperature above the glass transition temperature of the aromatic vinyl polymer block. Just do it.

In the above process, a petroleum resin is put into a kneader, the petroleum resin is heated until the temperature of the petroleum resin reaches a temperature equal to or higher than the softening point of the petroleum resin, and then block copolymerization is performed in the kneader. A kneaded product can be obtained by introducing the coalescence and kneading the block copolymer and the petroleum resin. Alternatively, a kneaded product can be obtained by first charging the block copolymer into a kneader and then charging the petroleum resin into the kneader and kneading the block copolymer and the petroleum resin. . The block copolymer and the petroleum resin may be continuously supplied to a continuous kneader and kneaded to obtain a kneaded product. The form of the block copolymer and petroleum resin to be added is not particularly limited, but from the viewpoint of handleability before kneading and ease of kneading, pellets, crumbs, flakes and the like are preferably used. be done. Substantially, in the production process of the block copolymer and the petroleum resin, the composition of the present invention is characterized by kneading both in advance to obtain a kneaded product at the stage before molding them into a product. It is most preferable from the viewpoint of maximizing the workability and minimizing the heat history until the final pressure-sensitive adhesive composition is obtained.

The composition of the present invention also contains
obtaining a block copolymer by polymerization;
After removing the solvent from the resulting block copolymer by steam stripping, the block copolymer is dried using an extruder or an expansion dryer;
a step of obtaining a petroleum resin by polymerization;
a step of drying the obtained petroleum resin using a thin film dryer;
It can also be produced by a production method including a step of obtaining a pellet-like or crumb-like composition by kneading the dried block copolymer and the dried petroleum resin in a molten state. .

The composition of the present invention also contains
a step of obtaining a block copolymer by polymerization;
After removing the solvent from the block copolymer by steam stripping, the block copolymer is melted using an extruder or kneader and dried to obtain a pellet-like or crumb-like composition. process,
a step of obtaining a petroleum resin by polymerization;
A step of drying the obtained petroleum resin using a thin film dryer,
A production method in which the dried petroleum resin is put into the extruder or the kneader containing the block copolymer in a molten state, and the block copolymer and the petroleum resin are both melted and kneaded. , can be manufactured.
The petroleum resin may be charged into the extruder or the kneader in a pre-melted state, or may be charged after being molded once and melted in the extruder or the kneader before use.

The kneading temperature for kneading the block copolymer and the petroleum resin may be determined in consideration of the glass transition temperature of the block copolymer, the softening point of the petroleum resin, and the deterioration temperature of each, and is not particularly limited. , The set temperature of the kneader is preferably 110 to 250°C, more preferably 120 to 230°C.

It can be judged that the kneading of the block copolymer and the petroleum resin is completed when the block copolymer and the petroleum resin are sufficiently kneaded. A specific determination method may follow a conventional method. For example, when a particulate block copolymer and petroleum resin are put into a kneader, particles of the block copolymer and petroleum resin are added to the kneaded product. It can be judged that the kneading is completed when the contour of is no longer visible.

Applications of the composition of the present invention are not particularly limited, and it can be used in applications where conventional aromatic vinyl-conjugated diene block copolymers are used, such as elastic films, gloves, elastic bands, condoms, OA equipment, various rolls for office use, anti-vibration sheets for electrical and electronic equipment, anti-vibration rubber, shock-absorbing sheets, shock-absorbing films and sheets, damping sheets for housing, molding materials used for damping materials, etc. It can be used for adhesive applications such as adhesive tapes, adhesive sheets, adhesive labels, and dust removal rollers, adhesive applications for hygiene products and bookbinding, and elastic fiber applications for clothing and sporting goods. .

The compositions of the present invention are also available as precompounds containing block copolymers and petroleum resins. In particular, it is suitable for use as a masterbatch for producing a hot-melt pressure-sensitive adhesive composition.

(Hot-melt adhesive composition)
The hot-melt pressure-sensitive adhesive composition of the present invention contains the above-described composition of the present invention (hereinafter sometimes referred to as "composition (A) of the present invention") and a plasticizer.

The hot melt adhesive composition of the present invention preferably contains 100 parts by weight of block copolymer, 25 to 400 parts by weight of petroleum resin, and 1 to 200 parts by weight of plasticizer. Unless otherwise specified, the content of the block copolymer and petroleum resin is the content of the block copolymer and petroleum resin contained in the composition (A) of the present invention, and the block copolymer for dilution, which is optionally used. It is the total content of polymer and diluent petroleum resin content.

The amount of the petroleum resin compounded in the hot-melt adhesive composition of the present invention is preferably 25 to 400 parts by weight, more preferably 50 to 350 parts by weight, per 100 parts by weight of the block copolymer. , more preferably 60 to 300 parts by weight.

The plasticizer is not particularly limited, but an organic compound that is liquid at room temperature (23° C.) is preferably used. Such a plasticizer is not particularly limited as long as it exhibits compatibility with the block copolymer. or naphthenic process oils; liquid polymers such as polybutene and polyisobutylene; Among these, paraffinic process oils and naphthenic process oils are particularly preferred. A plasticizer can be used individually by 1 type or in combination of 2 or more types.

The amount of the plasticizer in the hot melt adhesive composition of the present invention is preferably 1 to 200 parts by weight, more preferably 1 to 150 parts by weight, and further preferably 1 to 150 parts by weight, based on 100 parts by weight of the block copolymer. It is preferably 2 to 100 parts by weight. By setting the blending amount of the plasticizer within the above range, the viscosity characteristics can be improved while suppressing bleeding.

The hot melt adhesive composition of the present invention further contains a block copolymer for dilution and/or a petroleum resin for dilution in addition to the composition (A) of the present invention described above and a plasticizer. can do. Such a hot-melt adhesive composition can be produced by adding a plasticizer, a block copolymer for dilution and/or a petroleum resin for dilution to the composition (A) of the present invention. can be done.

The block copolymer for dilution and the petroleum resin for dilution are the block copolymer and The petroleum resin is a separate block copolymer and petroleum resin, the same or different from the block copolymer and petroleum resin already contained in the composition (A) of the present invention. "Homogeneous" means that all properties such as composition, melt index and softening point are the same, and "heterogeneous" means that any property is different.

The hot melt adhesive composition of the present invention uses the composition (A) of the present invention as a masterbatch, the composition (A) of the present invention, a plasticizer, optionally a block copolymer, and optionally It can be produced by kneading petroleum resin.

The composition (A) of the present invention contains block copolymers and petroleum resins that can be added to the composition (A) of the present invention when producing the hot-melt adhesive composition of the present invention. The same or different block copolymers and petroleum resins can be used. The use of different types has the advantage that the properties of the hot-melt pressure-sensitive adhesive composition can be appropriately adjusted. For example, it is possible to use a block copolymer having a different melt index from the block copolymer contained in the composition (A) of the present invention. For example, since a block copolymer with a small melt index tends to be inferior in moldability, a block copolymer with a small melt index is preliminarily kneaded with a petroleum resin to obtain the composition (A) of the present invention. By further blending a block copolymer having a higher melt index into the obtained composition (A), a hot melt pressure-sensitive adhesive composition can be easily produced. The melt viscosity of the adhesive composition can be adjusted appropriately, and the high-temperature properties can be improved.

Specific examples of the block copolymer and petroleum resin that can be added to the composition (A) of the present invention when producing the hot-melt adhesive composition of the present invention include the composition (A) of the present invention. The block copolymers and petroleum resins contained in include those mentioned above.

The content of the block copolymer for dilution in the hot-melt pressure-sensitive adhesive composition of the present invention is not particularly limited, and can be appropriately adjusted according to the physical properties of the target hot-melt pressure-sensitive adhesive composition. can.

The content of the diluent petroleum resin in the hot-melt pressure-sensitive adhesive composition of the present invention is not particularly limited, and can be appropriately adjusted according to the desired physical properties of the hot-melt pressure-sensitive adhesive composition.

However, from the viewpoint of expressing good initial adhesive strength at low temperature and excellent high temperature properties, which are characteristics of the composition (A) of the present invention, the block copolymer for dilution and the petroleum resin for dilution The total content is preferably 500 parts by weight or less, more preferably 350 parts by weight or less, and further preferably 200 parts by weight or less with respect to 100 parts by weight of the composition (A) of the present invention. preferable.

Moreover, the hot-melt pressure-sensitive adhesive composition of the present invention may contain other polymers as components other than the components described above. Such other polymers include, but are not particularly limited to, polybutadiene, conjugated diene homopolymers such as polyisoprene, (styrene-butadiene) random copolymers, (styrene-isoprene) random copolymers, and other aromatic polymers. Room temperature of vinyl-conjugated diene random copolymer, aromatic vinyl homopolymer such as polystyrene, isobutylene polymer, acrylic polymer, ester polymer, ether polymer, urethane polymer, polyvinyl chloride, etc. Polymers having elasticity at (23° C.) can be mentioned. Another polymer can be used individually by 1 type or in combination of 2 or more types. The amount of the other polymer blended in the hot-melt pressure-sensitive adhesive composition of the present invention is not particularly limited, but is preferably 20 parts by weight or less, more preferably 100 parts by weight of the block copolymer. is 10 parts by weight or less.

In addition, the hot-melt pressure-sensitive adhesive composition of the present invention may optionally contain a cross-linking agent. Examples of the cross-linking agent include, but are not limited to, peroxide cross-linking agents, sulfur-based cross-linking agents, and photopolymerization initiators.

The amount of the cross-linking agent in the hot-melt adhesive composition of the present invention is preferably in the range of 0.01 to 50 parts by weight, more preferably 0 parts by weight, relative to 100 parts by weight of the block copolymer. 0.01 to 20 parts by weight, more preferably 0.01 to 10 parts by weight.

The hot-melt adhesive composition of the present invention may also optionally contain an antioxidant. Antioxidants include, but are not limited to, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl -4-hydroxyphenyl)propionate, 2,6-di-t-butyl-p-cresol, di-t-butyl-4-methylphenol and other hindered phenolic compounds; carboxylate esters; phosphites such as tris(nonylphenyl)phosphite; and the like. Antioxidants can be used singly or in combination of two or more. The content of the antioxidant in the hot-melt pressure-sensitive adhesive composition of the present invention is not particularly limited, but is preferably 10 parts by weight or less, more preferably 10 parts by weight with respect to 100 parts by weight of the block copolymer. It ranges from 0.01 to 5 parts by weight.

Further, other compounding agents such as waxes, heat stabilizers, ultraviolet absorbers and fillers can be added to the hot-melt pressure-sensitive adhesive composition of the present invention. The hot-melt pressure-sensitive adhesive composition of the present invention is preferably a solventless composition containing no solvent.

The method for preparing the hot-melt pressure-sensitive adhesive composition of the present invention is not particularly limited, and may be prepared by mixing the composition (A) of the present invention described above with each of the components described above. Examples thereof include a method of dissolving each component in a solvent, mixing them uniformly and then removing the solvent by heating, and a method of melting and mixing each component with a kneader or the like. Among these methods, melt mixing is preferred from the viewpoint of more efficient mixing. The temperature for melt-mixing is not particularly limited, but is usually in the range of 100 to 200°C.

Further, the composition (A) of the present invention, a plasticizer, optionally used block copolymer and petroleum resin are dissolved in n-hexane, cyclohexane, benzene, toluene or the like to prepare a solution-type adhesive composition. may be That is, the hot-melt adhesive composition of the present invention may be a solution-type adhesive composition.

The use of the hot-melt pressure-sensitive adhesive composition of the present invention (target to be adhered) is not particularly limited, and it can be used for various types of adhesion to which hot-melt adhesion can be applied. Among others, it is particularly suitable for use as a so-called tape pressure-sensitive adhesive, in which the pressure-sensitive adhesive composition is melt-coated on a film-like substrate. For example, the hot-melt pressure-sensitive adhesive composition of the present invention can be melted by heating and then melt-coated on a substrate to form a pressure-sensitive adhesive tape, which can be attached to an adherend by pressing. In this case, the properties of the hot-melt pressure-sensitive adhesive composition can also be adjusted by cross-linking the hot-melt pressure-sensitive adhesive composition. The hot-melt pressure-sensitive adhesive composition of the present invention has good hot-melt properties, and therefore contributes to the reduction of the defective product rate and the improvement of productivity in the production of such tapes. Moreover, the resulting tape has excellent initial adhesive strength at low temperatures and excellent heat resistance stability at high temperatures. Therefore, the hot-melt adhesive composition of the present invention can be used not only for packaging tapes and general-purpose labels, but also for heat-resistant tapes such as masking tapes, heat-resistant labels, tapes used in low-temperature environments, food labels, and freezer labels. It is also suitably used for labels and the like. The hot-melt adhesive composition of the present invention can also be used for sanitary goods such as disposable paper diapers and sanitary napkins; food packaging such as frozen foods, fresh foods and confectionery; member packaging such as automobile parts and mechanical parts; Packing of electrical products such as products and refrigerators; Bookbinding applications such as slips, books, and catalogs; Bag making applications such as craft bags, polypropylene bags, and polyethylene bags; It can also be suitably used for clothing applications such as adhesion of interlining.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. In the following, "parts" are by weight unless otherwise specified. In addition, the test and evaluation were as follows.

<Styrene unit content>
The styrene unit content of the block copolymer was determined based on proton NMR measurements.

<Melt index>
The melt index of the block copolymer was measured according to ASTM D1238 (G condition, 200°C, 5 kg load).

<Softening point>
The softening point of the petroleum resin was measured by the ring and ball method according to JIS K2207.

<Dynamic viscoelasticity measurement>
The dynamic viscoelasticity measurement of the composition and the hot-melt pressure-sensitive adhesive composition was performed according to the following procedure. First, the composition and the hot-melt pressure-sensitive adhesive composition were press-molded to prepare test pieces having a length of 50 mm, a width of 10 mm, and a thickness of 1 mm. Using this test piece, based on JIS K7244-4, using a viscoelasticity measuring device (TA Instrument Japan Co., Ltd., ARES), the temperature is increased in the range of -100 ° C to +150 ° C. Viscoelastic spectra were measured at a rate of 5°C/min. The glass transition temperature (Tg) of the composition and the glass transition temperature (Tg) of the hot-melt adhesive composition were obtained from the peak top temperature on the low temperature side of the loss tangent tan δ.

<Pellet formability>
The compositions were fed to a single screw extruder equipped with an underwater hot cut device at the tip of the extruder, extruded through a die and evaluated according to the following criteria.
A: Cylindrical pellets having an average diameter of 3 mm and an average length of about 4 mm were obtained.
○: Cylindrical pellets having an average diameter of 3 mm and an average length of about 4 mm were obtained, but some of the pellets adhered to each other.
x: Could not be molded.

<Workability>
100 parts by weight of the composition, 25 parts by weight of petroleum resin C, and 25 parts by weight of naphthenic oil were charged into a desktop kneader heated to 160° C. and kneaded at 100 rpm. The time from the start of kneading to uniform kneading was measured and evaluated according to the following criteria.
A: Uniformly kneaded within 30 minutes.
◯: Uniformly kneaded within 1 hour over 30 minutes.
Δ: Uniformly kneaded for more than 1 hour and less than 2 hours.
x: It took 2 hours or more for uniform kneading.

<Blocking resistance>
The composition was fed to a single screw extruder equipped with an underwater hot cut device at the extruder tip, extruded through a die and pelletized. To the pellets of the resulting composition, immediately after pelletization, 0.5 parts by weight of talc per 100 parts by weight of the composition was added as an anti-adhesion agent, and uniformly adhered to the surface of the composition. .
50 g of composition pellets were placed in a polyethylene bag of 10 cm×10 cm, a weight of 6 kg was placed thereon, and the bag was held in an oven at 60° C. for 70 hours and evaluated according to the following criteria.
A: There was no blocking at all.
◯: Light blocking occurred, but crumbled when touched.
Δ: Blocking occurred, but collapsed when force was applied.
x: Blocking occurred, and did not crumble even when force was applied.

<Initial adhesive strength>
A loop tack test was performed at 0° C. according to FINAT-1991 FTM-9 (Quick-stick tack measurement). A specular stainless steel plate was used as the adherend. The larger the value, the better the initial adhesive strength.

<Example 1>
(Preparation of composition)
Styrene-isoprene block copolymer SIS-A (trade name "Quintac (registered trademark) 3530", manufactured by Nippon Zeon) 50 parts, and petroleum resin A (trade name "Quinton (registered trademark) B170", Nippon Zeon Co., Ltd.) is put into a stirring blade type kneader, the inside of the system is replaced with nitrogen gas, and then kneaded at 160 to 180 ° C. until the block copolymer and petroleum resin are uniformly kneaded. A composition was prepared by Also, using the obtained composition, dynamic viscoelasticity was measured, and pellet moldability and blocking resistance were evaluated. In addition, processability was evaluated when used in a hot-melt pressure-sensitive adhesive composition. Table 1 shows the results.

<Example 6>
(Preparation of hot-melt adhesive composition)
100 parts of the composition obtained in Example 1 was put into a stirring blade type kneader, and styrene-isoprene block copolymer SIS-B (trade name “Quintac (registered trademark) 3620”, Nippon Zeon Co., Ltd. ) 50 parts, petroleum resin C (trade name “Quinton (registered trademark) R100”, manufactured by Nippon Zeon) 50 parts, paraffin-based process oil (trade name “Diana Process Oil PW-90”, manufactured by Idemitsu Kosan Co., Ltd.) 20 Part, 1 part of antioxidant (Irganox 1010, manufactured by BASF) is added, the system is replaced with nitrogen gas, and then kneaded at 160 to 180 ° C. for 2 hours to obtain a hot melt adhesive composition. prepared the product. Using the obtained hot-melt pressure-sensitive adhesive composition, dynamic viscoelasticity was measured, and initial adhesive strength was evaluated. Table 2 shows the results.

<Examples 2-5, Comparative Examples 1-2 and Comparative Example 5>
A composition was prepared and evaluated in the same manner as in Example 1, except that the type and amount of the block copolymer and the type and amount of the petroleum resin were changed as shown in Table 1. Table 1 shows the results.

<Examples 7 to 10, Comparative Examples 6 to 8>
A hot-melt pressure-sensitive adhesive composition was prepared and evaluated in the same manner as in Example 6, except that the type of composition and the amount of each component were changed as shown in Table 2. Table 2 shows the results.

<Comparative Examples 3-4>
A composition was prepared in the same manner as in Example 1, except that the type and amount of the block copolymer and the type and amount of the petroleum resin were changed as shown in Table 1. Pellet moldability was evaluated using the resulting composition, but the adhesive strength was too high to form pellets. Moreover, no hot-melt pressure-sensitive adhesive compositions were prepared using the compositions obtained in Comparative Examples 3 and 4.

The styrene-isoprene block copolymers and petroleum resins shown in Tables 1 and 2 represent the following, respectively.
SIS-A: Trade name "Quintac (registered trademark) 3530", manufactured by Nippon Zeon Co., Ltd., styrene unit content 16.5% by mass, melt index 1 g / 10 minutes SIS-B: Trade name "Quintac (registered trademark) 3620", Nippon Zeon Co., Ltd., styrene unit content 14% by mass, melt index 9 g / 10 minutes SIS-C: trade name "Quintac (registered trademark) 3280", Nippon Zeon Co., Ltd., styrene unit content 25% by mass , Melt index 11 g / 10 minutes Petroleum resin A: Trade name "Quinton (registered trademark) B170", manufactured by Nippon Zeon Co., Ltd., aliphatic hydrocarbon resin, softening point 70 ° C.
Petroleum resin B: Trade name "Quinton (registered trademark) N180", manufactured by Nippon Zeon Co., Ltd., aliphatic-aromatic copolymer hydrocarbon resin, softening point 80 ° C.
Petroleum resin C: trade name "Quinton (registered trademark) R100", manufactured by Nippon Zeon Co., Ltd., aliphatic hydrocarbon resin, softening point 96 ° C.

As the results of Examples 1 to 5 in Table 1 show, the contents of the block copolymer and the petroleum resin are appropriately adjusted, the petroleum resin does not contain a softening agent, and has a softening point of 90 ° C. or less. and having an appropriately adjusted glass transition temperature was excellent in moldability, workability and blocking resistance. In addition, as the results of Examples 6 to 10 in Table 2 show, the contents of the block copolymer and the petroleum resin are appropriately adjusted, do not contain a softening agent, and have a softening point of 90 ° C. or less. A composition containing a petroleum resin and having an appropriately adjusted glass transition temperature could provide a hot-melt pressure-sensitive adhesive composition with excellent initial adhesive strength at low temperatures.

On the other hand, as shown by the results of Comparative Examples 6 and 7 in Table 2, the composition containing a petroleum resin having a softening point of over 90°C is a hot melt adhesive composition having excellent initial adhesive strength at low temperatures. could not give
Further, as shown in the results of Comparative Examples 3 and 4 in Table 1, when the amount of the block copolymer is too small, the adhesive strength is too high to be molded into pellets, and Comparative Example 5 in Table 1 cannot be formed. As shown in the results of 1., when the amount of the block copolymer was too large, the workability was poor. Furthermore, as shown by the results of Comparative Example 8 in Table 2, when the amount of the block copolymer was too large, it was not possible to provide a hot-melt pressure-sensitive adhesive composition with excellent initial adhesive strength at low temperatures.

Claims (8)

For obtaining a hot-melt adhesive composition by mixing an organic compound that is liquid at 23° C. with an optionally blended block copolymer for dilution and/or an optionally blended petroleum resin for dilution. , a pelletized or crumb-shaped masterbatch,
A masterbatch block copolymer having at least one aromatic vinyl polymer block and at least one conjugated diene polymer block, and a masterbatch petroleum resin containing a process oil and a liquid polymer. figure,
The content of the masterbatch block copolymer in the masterbatch is in the range of 30 to 97% by mass, and the content of the masterbatch petroleum resin in the masterbatch is 3 to 70% by mass. is the range and
The softening point of the masterbatch petroleum resin is 90° C. or less,
The glass transition temperature of the masterbatch measured by dynamic viscoelasticity measurement is less than 0 ° C.,
The glass transition temperature is obtained as the peak top temperature on the low temperature side of the loss tangent tan δ of the viscoelastic spectrum obtained by performing dynamic viscoelasticity measurement at a heating rate of 5 ° C./min based on JIS K7244-4. masterbatch that is. A pellet-shaped or crumb-shaped masterbatch for obtaining a hot-melt adhesive composition by mixing with an organic compound that is liquid at 23° C., and a block copolymer for dilution and/or a petroleum resin for dilution A masterbatch according to claim 1. The masterbatch block copolymer is at least one selected from aromatic vinyl-conjugated diene block copolymers, aromatic vinyl-conjugated diene-aromatic vinyl block copolymers, and mixtures thereof. A masterbatch according to claim 1 or 2. The content of the masterbatch block copolymer in the masterbatch is in the range of 50 to 90% by mass, and the content of the masterbatch petroleum resin in the masterbatch is 10 to 50% by mass. The masterbatch according to any one of claims 1 to 3, which is in the range. The petroleum resin for the masterbatch is at least one selected from the group consisting of aliphatic hydrocarbon resins, aliphatic-aromatic copolymer hydrocarbon resins, and hydrides thereof. A masterbatch according to any one of The masterbatch according to any one of claims 1 to 5, wherein the softening point of the masterbatch petroleum resin is 80°C or less. The method for producing a masterbatch according to any one of claims 1 to 6, comprising a step of kneading the masterbatch block copolymer and the masterbatch petroleum resin in a molten state. Method. The masterbatch according to any one of claims 1 to 6, an organic compound that is liquid at 23° C., and an optionally blended block copolymer for dilution and/or an optionally blended petroleum resin for dilution are mixed. A method for producing a hot-melt pressure-sensitive adhesive composition comprising steps.