JP3323276B2 - High molecular weight acrylic polymer and its use - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, acrylic rubber, pressure sensitive adhesives, sealants, vibration damping agents, relates to a resin modifier, a high molecular weight acrylic polymer and its APPLICATIONS used in asphalt additives .

[0002]

2. Description of the Related Art High molecular weight acrylic polymers are used in acrylic rubber, pressure sensitive adhesives, sealing agents, vibration damping agents, resin modifiers, asphalt additives and the like. This high molecular weight acrylic polymer is generally produced by radically polymerizing a monomer component containing an acrylic acid monomer as a main component to a high conversion. Radical polymerization is generally performed by emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization.

In emulsion polymerization, suspension polymerization and solution polymerization, the polymerization is carried out by dispersing monomers in a dispersion medium, so that the polymerization temperature is easy to control, and the reaction solution is easy to flow even when the polymerization rate is high. Although it has advantages, it has the following disadvantages. In emulsion polymerization and suspension polymerization, a precipitation step (necessary in the case of emulsion polymerization), a filtration step, a washing step, and a drying step are required to remove the polymer from the dispersion medium, and the operation is very complicated. In addition to poor productivity, a surfactant such as an emulsifier or a dispersant is mixed into the obtained acrylic polymer, so that it is difficult to obtain a pure polymer. The acrylic polymer in which the surfactant remains remains poor in water resistance and further deteriorates in strength or cohesion depending on the use. When a high-molecular-weight acrylic polymer is produced by emulsion polymerization or suspension polymerization, a gel component is generated and the fluidity is poor. When performing copolymerization by emulsion polymerization or suspension polymerization, it is necessary to use a plurality of types of monomers having different hydrophilicities depending on the desired polymer composition, but emulsification or suspension may not be possible, and the resulting There is a restriction on the composition of the acrylic polymer.

[0004] In solution polymerization, a large amount of organic solvent is used as a dispersion medium, so that a large amount of low molecular weight substances are generated, and the molecular weight distribution of the acrylic polymer tends to be large, and the heat resistance or processing workability of the polymer is low. descend. On the other hand, bulk polymerization does not use a dispersion medium and does not require the above-mentioned surfactant, and therefore has no disadvantages as described above and is an industrially advantageous method. However, when a polymerizable monomer whose polymerization reaction is too radical is bulk-polymerized, it is difficult to control the polymerization. For this reason, depending on the type of monomer, it is difficult to increase the molecular weight of the polymer or to design the molecular weight distribution, or gelling or degraded substances are generated due to rapid heat generation during polymerization, or in the worst case, an explosion Or invite.

[0005] Among the polymerizable monomers, styrene and methyl methacrylate are known to be capable of controlling polymerization in bulk polymerization, and studies on bulk polymerization have been carried out for a long time and industrialized. Styrene-based polymers are industrially manufactured by bulk polymerization of styrene or a monomer mixture mainly composed of styrene to a high polymerization rate in the presence or absence of a polymerization initiator, and volatilization of a small amount of unreacted styrene. Is obtained.

In the bulk polymerization of methyl methacrylate, methyl methacrylate or a monomer mixture mainly composed of methyl methacrylate is polymerized in the presence of a polymerization initiator. At a high polymerization rate, a polymer having a narrow molecular weight distribution is obtained. Therefore, polymerization is stopped at a low polymerization rate of about 60% to volatilize a large amount of unreacted monomer. This is because the polymerization rate of methyl methacrylate is higher than that of styrene, and the higher the polymerization rate, the faster the polymerization rate due to the gel effect (a phenomenon in which the polymerization rate increases as the polymerization proceeds and the viscosity of the reaction mixture increases). This is because a temperature distribution occurs in the liquid, and a portion where the polymerization does not proceed very much and a portion where the polymerization proceeds rapidly are mixed.

As described above, since even methyl methacrylate, whose polymerization reaction is much slower than that of an acrylic acid monomer such as acrylic acid or acrylic acid ester, stops bulk polymerization at a low polymerization rate. For this reason, bulk polymerization of acrylic acid monomers, in which the polymerization reaction is more severe than methyl methacrylate, is difficult to control the temperature and is not generally used at all. JP-B-62-41523 and JP-B2
No. 55448 proposes bulk polymerization of acrylic acid monomers using a screw extruder. In the bulk polymerization of acrylic acid monomers proposed in these publications, a polymerization initiator and an acrylic acid monomer are introduced into a screw extruder having a specific structure, and the viscosity is reduced in a short time by utilizing a rapid reaction. Is raised so that liquid can be sent by a screw.

[0008]

When a high molecular weight acrylic polymer is used for various purposes, the high molecular weight component of the polymer exhibits the required performance, and the low molecular weight component causes a decrease in performance. . Therefore, a high molecular weight acrylic polymer having a small molecular weight distribution is desired. According to the method described in the above publication, since the temperature of the reaction solution rises stepwise, not rapidly, as the polymerization rate rises, it is possible to carry out bulk polymerization of the acrylic acid monomer without causing a runaway reaction. However, the obtained acrylic polymer contains a large amount of low molecular weight components and has a very large molecular weight distribution Mw / Mn of about 8 to 13, so that the heat resistance or processing workability is poor.

In addition, since the bulk polymerization described in the above publication utilizes a rapid reaction of an acrylic acid monomer, it can be carried out on a small scale such as a laboratory level, but is not safe on an industrial scale. Considering the above, implementation is difficult. At present, there are few low molecular weight components,
The fact is that there is no technology for producing an acrylic polymer having a narrow molecular weight distribution and a high molecular weight and containing no surfactant, with good industrial productivity and safety.

The present invention provides a high-molecular-weight acrylic polymer which does not contain a surfactant, has a limited polymer composition, and is excellent in heat resistance, processing workability and fluidity, and its use .

[0011]

According to the present invention, there is provided a high-molecular-weight acrylic polymer obtained by bulk polymerization, having a structure of CH ₂ ＣＨCHCO—.
Oxazoline group, aziridine group, epoxy group, hydride
Roxyl group, carboxyl group, reactive halogen, amide
At least one frame selected from a group consisting of
Have the bridge functional group which may monomer units (a) 51
Wherein wt% or more, oxazoline group, aziridine group, Epo
Xyl group, hydroxyl group, carboxyl group, reactive halo
Gen, amide group, organosilicon group and reactive double bond group
At least one crosslinkable functional group selected from the group consisting of 0.005
Having a structure having a molecular weight of mmol1.4 mmol / g and a number average molecular weight of 6.6.
1,000,000, a weight average molecular weight from 256,000 to 108.1
10,000, glass transition temperature of 0 ° C. or less and molecular weight distribution (Mw /
(Mn) 5 or less. The monomer unit other than the monomer unit (a) may be a monomer unit (b-1) and / or (b)
-2). In the following, “CH ₂ ＣＨCHCO
-Monomer having a structure of-
You may say. Also, the structure of “CH ₂ −CHCO—
Oxazoline, aziridine, epoxy,
Droxyl group, carboxyl group, reactive halogen, amine
At least one selected from the group consisting of
"Monomer which may have a crosslinkable functional group"
Acrylic acid monomer which may have functional groups "
There is a case.

The acrylic polymer of the present invention has the following problems if the amount of the crosslinkable functional group, the number average molecular weight, the glass transition temperature and the molecular weight distribution are out of the above ranges. When the number average molecular weight is less than 66,000 , the workability of processing the polymer is low, and when it exceeds 1,000,000, the fluidity of the polymer is poor. When the molecular weight distribution exceeds 5, the heat resistance or processing workability of the polymer is poor. When the glass transition temperature is higher than 0 ° C., the performance as a high molecular weight acrylic polymer is not exhibited. If the amount of the crosslinkable functional group contained in the polymer is out of the above range, there is a problem that the strength is insufficient, the cohesion is insufficient, the elongation is small, and the solid becomes brittle, regardless of the use.

[0013] This invention provides the use of high molecular weight acrylic polymer of the present invention. Among the high molecular weight acrylic polymers of the present invention, those having a crosslinkable functional group
Also observed an acrylate monomer units (a) 60 to 100 [duplex <br/> weight% containing, oxazoline group, aziridine group, an epoxy
Group, hydroxyl group, carboxyl group, reactive halogen
Group, amide group, organosilicon group and reactive double bond group
At least one crosslinkable functional group selected from 0.01 to
Those having 1.4 mmol / g and having a number average molecular weight of 200,000 to 1,000,000 and a molecular weight distribution (Mw / Mn) of 3 or less are suitably used for acrylic rubber.

The acrylic rubber of the present invention contains the high molecular weight acrylic polymer for acrylic rubber as a main component. In the high molecular weight acrylic polymer for acrylic rubber of the present invention and the acrylic rubber, the amount of the monomer unit (a);
When the amount of the crosslinkable functional group, the number average molecular weight, the glass transition temperature, and the molecular weight distribution are out of the above ranges, the following problems occur. When the monomer unit (a) is less than 60% by weight, oil resistance or heat resistance, which is a characteristic of acrylic rubber, is reduced. If the amount of the crosslinkable functional group is less than 0.01 mmol / g, the strength of the acrylic rubber is inferior. If it exceeds 1.4 mmol / g, the scorch time is too short or the elongation of the rubber is too small. Number average molecular weight is 20
The glass transition temperature is preferably from -70 ° C to -500,000.
10 ° C. is preferable, and the molecular weight distribution is preferably 1.0 to 2.5. If the number average molecular weight is less than 200,000, stickiness to the roll is recognized during the mixing operation with an open roll, and the workability is poor. If it exceeds 1,000,000, the flowability is poor and the moldability is poor. If the glass transition temperature exceeds 0 ° C., rubber-like performance is not sufficiently exhibited. If the molecular weight distribution exceeds 3, the mixing efficiency of the open roll is poor due to too much low molecular weight component, or the moldability is poor due to too much high molecular weight component.

Such a high-molecular-weight acrylic polymer for an acrylic rubber is generally used with a vulcanizing agent (crosslinking agent) and other components (eg, a reinforcing agent, a filler, an antioxidant, a plasticizer, and a lubricant). ), Generally at 120 ° C
By heating and crosslinking as described above, an acrylic rubber is obtained. After crosslinking, it may be mixed with the above other components. The composition for producing the acrylic rubber is not particularly limited. For example, among all components, a vulcanizing agent (crosslinking agent) 0.1 to 1
0% by weight, reinforcing agent or filler 0-60% by weight, antioxidant 0-10% by weight, plasticizer 0-10% by weight, lubricant 0-0
2% by weight, and 8 to 99.9% by weight of the high molecular weight acrylic polymer for acrylic rubber of the present invention. The acrylic rubber obtained in this way has the advantages of being compatible with mixing workability and moldability, and having high water resistance and high strength as compared with conventional ones, and has various sealing materials (gaskets, packings,
O-rings, oil seals, etc.), various hoses, coating materials, etc., as well as various belts and rolls.

Here, examples of the vulcanizing agent (crosslinking agent) include zinc dimethyldithiocarbamate, maleic acid, methoxymethylmelamine, o-cresol novolak epoxy, diaminodiphenylmethane and the like. Examples of the reinforcing agent or filler include carbon black, silica-based silicic anhydride, calcium carbonate, and talc. Examples of the anti-aging agent include phenyl-1-naphthylamine, 2-mercaptobenzimidazole, nickel diethyldithiocarbamate and the like. As plasticizers, polymer ester-based Paraplex G-25 (manufactured by Rohm & Haas), Adecaizer P-200 (manufactured by Asahi Denka)
And the like. Examples of the lubricant include stearic acid and the like.

Among the high molecular weight acrylic polymers of the present invention, the number average molecular weight of 66,000 to 500,000 and -30
Those having a glass transition temperature of not more than ° C are suitably used for pressure-sensitive adhesives. The pressure-sensitive adhesive of the present invention comprises this high-molecular-weight acrylic polymer for a pressure-sensitive adhesive as an adhesive component.

In the high-molecular-weight acrylic polymer for a pressure-sensitive adhesive and the pressure-sensitive adhesive of the present invention, when the amount of the crosslinkable functional group, the number average molecular weight, the glass transition temperature, and the molecular weight distribution are out of the above ranges. There are the following problems. If the amount of the crosslinkable functional group is less than 0.005 mmol / g, the cohesive strength is inferior and 1.4.
If it exceeds mmol / g, the adhesive strength is poor. Number average molecular weight is 6.6
The glass transition temperature is preferably −40 ° C. or less, and the molecular weight distribution is preferably 1.0 to 4.0.
When the number average molecular weight is less than 66,000, there are problems that the cohesive strength is insufficient, heat resistance is reduced, adhesive residue is easily generated at the time of re-peeling, or a large amount of a crosslinking agent is required. If it exceeds 10,000, the fluidity of the polymer is poor, the coatability of the polymer is reduced, and the miscibility with other components used in the pressure-sensitive adhesive is reduced. If the glass transition temperature is higher than -30 ° C, the tackiness is not sufficiently exhibited. If the molecular weight distribution is more than 5, the amount of low molecular weight components is too large, so that heat resistance is lowered and adhesive residue is apt to be generated at the time of re-peeling. Acrylic acid-based monomer unit (a) is 5 to 100 wt% of the polymer. It is characteristic tack of a pressure sensitive adhesive monomer unit (a) is a less than 51% by weight you decrease.

Such a high-molecular-weight acrylic polymer for a pressure-sensitive adhesive can be used as a pressure-sensitive adhesive by itself, or a compounding component such as a cross-linking agent, a solvent, a tackifier and the like which are usually used. Combines to form a pressure-sensitive adhesive. The latter pressure-sensitive adhesive composition is, for example, 100 parts by weight of a high-molecular-weight acrylic polymer for a pressure-sensitive adhesive of the present invention, 0 to 5 parts by weight of a crosslinking agent, 0 to 400 parts by weight of a solvent, and 0 to 400 parts by weight of a tackifier. It has a composition of 100 parts by weight. Examples of the crosslinking agent include an isocyanate compound, an epoxy compound, a melamine compound, and a metal chelate compound. Examples of the solvent include toluene, ethyl acetate, acetone and the like. Examples of the tackifier include rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin and its esterified product, terpene resin, terpene / phenol resin, petroleum resin and the like. The pressure-sensitive adhesive obtained in this way has the advantages of superior cohesion, water resistance, and high-temperature properties as compared with conventional adhesives, and has the advantage of having less adhesive residue upon re-peeling. Useful for applications such as films, labels, sheets and the like.

[0020] The preferred manufacturing method for obtaining a polymer containing a high molecular weight acrylic polymer such as the above mentioned, crosslinkable monomer having a crosslinkable functional group ( "oxazoline group, aziridine
Group, epoxy group, hydroxyl group, carboxyl group, anti-
Selected from reactive halogens, amide groups and organosilicon groups
Acrylic acid having at least one crosslinkable functional group
Monomer "and" oxazoline group, aziridine group, epoxy
Si, hydroxyl, carboxyl, reactive halogen
Group, amide group, organosilicon group and reactive double bond group
Having at least one crosslinkable functional group selected from
Total amount of other monomers copolymerizable with the lylic acid-based monomer ") in an amount of from 0.05 to 10% by weight, and having a crosslinkable functional group.
A method for producing a high-molecular-weight acrylic polymer by bulk-polymerizing a monomer component containing at least 51% by weight of an acrylic acid-based monomer, wherein the raw material for the bulk polymerization comprises the monomer component and the monomer component 0.001 to 1.0 based on 100 parts by weight of body components
And a mercaptan of the proportion of parts, Ru manufacturing method der high molecular weight acrylic polymer, characterized in that does not contain a polymerization initiator substantially.

The present inventors have conducted various studies on the bulk polymerization of acrylic acid monomers, which are said to be substantially impossible to perform bulk polymerization. As a result, the inventors found that "rapid heat generation due to a very high polymerization rate" was found. The present inventors have sought a technique that can be controlled, and have been able to arbitrarily design a copolymer composition, and have found a method of obtaining a polymer having a uniform molecular weight distribution. ADVANTAGE OF THE INVENTION According to this invention, rapid heat generation at the time of bulk polymerization can be suppressed and a moderate polymerization rate can be controlled, and a high molecular weight acrylic polymer having a uniform and small molecular weight distribution is produced.

In the case of bulk polymerization of a monomer component containing an acrylic acid monomer as a main component, it has been studied to make the polymerization system substantially free of a polymerization initiator. Even without substantially containing a polymerization initiator, in many cases, polymerization cannot be controlled due to rapid heat generation,
Sometimes it becomes a gel. The bulk polymerization of a monomer component containing an acrylic acid-based monomer as a main component proceeds gently to a high polymerization rate, controlling the molecular weight, obtaining a polymer having a small molecular weight distribution, and the polymerization system being polymerized. Mercaptan is used to solve the problems that occur even when the initiator is contained, not to mention when the initiator is substantially contained.
The role of mercaptan in the process of the present invention is important, and plays a role in controlling the polymerization rate and a role in controlling the molecular weight. During bulk polymerization, the polymerization system must include mercaptan. The amount of the mercaptan used is 0.001 to 1.0 part by weight based on 100 parts by weight of the total amount of the monomer components, and is 0.005 to 0.7 part.
Parts by weight are preferred. In the case of styrene and methyl methacrylate, bulk polymerization can be stably performed without a catalyst.However, since the polymerization rate of an acrylic acid monomer is high, a runaway reaction often occurs without a catalyst. .0
If the amount is less than 01 parts by weight, a rapid reaction occurs during the polymerization, which is not preferable. If the mercaptan is used in an amount exceeding 1.0 part by weight, a polymer having a low molecular weight component will be formed, which is not preferable.

The mercaptan used in the present invention is not particularly limited as long as it is an organic compound having an SH group, but alkyl mercaptans such as ethyl mercaptan, butyl mercaptan, hexyl mercaptan and dodecyl mercaptan; and phenyl mercaptan and benzyl mercaptan. such thiophenols; thioglycolic acid, 3-mercaptopropionic acid, carboxyl group-containing mercaptans such as thiosalicylic acid, esters of C ₁ -C ₁₈ alcohol and carboxyl group-containing mercaptans;
Hydroxyl-containing mercaptans such as 2-mercaptoethanol; diesters of diols such as ethylene glycol and 1,4-butanediol and carboxyl-containing mercaptans; compounds having three or more hydroxyl groups such as trimethylolpropane and pentaerythritol; Polyesters of carboxyl group-containing mercaptans; compounds having three or more mercapto groups such as trithioglycerin; compounds obtained by adding hydrogen sulfide to polyhydric epoxy compounds; mercaptoethanol esters of polycarboxylic acids; 2-mercaptobenzo Thiazole; 2-mercaptobenzimidazole and the like, and at least one of them is used.

The mercaptan used for preparing the high molecular weight acrylic polymer for acrylic rubber is preferably a compound having three or more mercapto groups. When such a mercaptan is used, the molecular weight distribution (Mw / M
An acrylic polymer having a narrow n) and a branched structure is formed, and a high-strength acrylic rubber can be obtained. The mercaptan used to make the high molecular weight acrylic polymer for the pressure-sensitive adhesive composition is preferably a compound having three or more mercapto groups. When such a mercaptan is used, the molecular weight distribution (Mw / Mn) is narrow at a high molecular weight,
An acrylic polymer having a branched structure is generated, and a pressure-sensitive adhesive having high cohesion can be obtained.

The monomer components used in the bulk polymerization for obtaining a high molecular weight acrylic polymer include acrylic acid monomer (A) and other monomers (B) copolymerizable therewith. It is composed of at least an acrylic acid monomer (A). The monomer component used in the present invention contains an acrylic acid monomer (A) as a main component, and usually comprises 51 to 100% by weight of the monomer (A) and the balance of the monomer (B). A crosslinkable monomer having a crosslinkable functional group, that is, a monomer component containing 0.05 to 10% by weight of at least one of monomers (A-1) and (B-1) described below. used.

When a high molecular weight acrylic polymer for acrylic rubber is produced, the monomers (A-1) and (B-
A monomer component containing 0.1 to 10% by weight of at least one of 1) is used. Monomers (A-1) and (B
When at least one of -1) is less than 0.1% by weight, the strength of the obtained acrylic rubber is inferior and 10% by weight.
If it is too high, the scorch time will be too short or the rubber will grow too little.

When producing a high molecular weight acrylic polymer for a pressure-sensitive adhesive, the monomers (A-1) and (B-1)
A monomer component containing 0.05 to 10% by weight of at least one of them is used. The monomers (A-1) and (B-
If at least one of 1) is less than 0.05% by weight, the cohesive strength and tackiness of the resulting pressure-sensitive adhesive will decrease, and if it exceeds 10% by weight, the initial tackiness (tack) will decrease. Therefore, it is not preferable.

When the monomer component is subjected to bulk polymerization, if the amount of the monomer (A) is less than 51% by weight, a polymer can be obtained safely and stably without applying the method of the present invention. If the amount of the monomer (A) is 51% by weight or more, bulk polymerization is difficult unless the method of the present invention is applied. In the case of producing a high molecular weight acrylic polymer for acrylic rubber, a monomer (A-
2) is used in an amount of 51% by weight or more, preferably 60% by weight or more. When preparing a high-molecular-weight acrylic polymer for a pressure-sensitive adhesive composition, the monomer (A-2) is added in an amount of 51% by weight or more, preferably 6%, for the purpose of keeping the glass transition temperature of the adhesive low.
Use 0% by weight or more.

A monomer having a structure of CH ₂ ＣＨCHCO—
( Acrylic acid monomer ) (A) is an oxazoline group,
Dilysine group, epoxy group, hydroxyl group, carboxy
Group, reactive halogen, amide group and organosilicon group
It is selected from those having at least one crosslinkable functional group (A-1) and those not having such a crosslinkable functional group (A-2). The monomer (A-1) has at least one crosslinkable functional group selected from an oxazoline group, an aziridine group, an epoxy group, a hydroxyl group, a carboxyl group, a reactive halogen, an amide group, and an organosilicon group. Specific examples of the monomer (A-1) include acrylic acid; an aziridine group-containing monomer such as acryloylaziridine and 2-aziridinylethyl acrylate; and glycidyl acrylate and 2-methylglycidyl acrylate. 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, monoester of acrylic acid with polypropylene glycol or polyethylene glycol, lactones and acrylic acid 2
A hydroxyl group-containing monomer such as an adduct of hydroxyethyl; a carboxyl group-containing monomer such as an ester of acrylic acid with a compound having a hydroxyl group and a carboxyl group, acrylic acid, and acrylate; Reactive halogen-containing monomers such as 2-chloroethyl;
Acrylamide, N-methylolacrylamide, N-
Amide group-containing monomers such as methoxymethyl acrylamide and N-butoxymethyl acrylamide; at least one selected from organic silicon group-containing monomers such as γ-acryloxypropyltrimethoxysilane and 2-acryloxyethoxytrimethoxysilane One.

The monomer (A-2) does not have a crosslinkable functional group as described above. Specific examples of the monomer (A-2) include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, nonyl acrylate Alkyl acrylates such as decyl acrylate, dodecyl acrylate and substituted products thereof; aryl acrylates such as phenyl acrylate and benzyl acrylate; methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate; Alkoxyalkyl acrylates such as ethoxypropyl acrylate; diacrylates of polyethylene glycol such as ethylene glycol, diethylene glycol and triethylene glycol; propylene glycol, dipro Diacrylates of polypropylene glycol such as lene glycol and tripropylene glycol; polyvalent acrylates such as trimethylolpropane triacrylate; acrylates of alicyclic alcohols such as cyclohexyl acrylate; , At least one of which is used.

The monomer (B) is another monomer copolymerizable with the acrylic acid monomer (A), and is an oxazolyl monomer.
Groups, aziridine groups, epoxy groups, hydroxyl groups,
Ruboxyl group, reactive halogen, amide group, organosilicon
At least one selected from a group and a reactive double bond group
At least one selected from those having a crosslinkable functional group (B-1) and those not having such a crosslinkable functional group (B-2). The monomer (B-1) is used in order to function as a cross-linking point in molding by hot pressing or the like or in pressure-sensitive adhesive processing. When a high molecular weight acrylic polymer is used for an acrylic rubber or a pressure-sensitive adhesive, the monomer (B-2) has properties such as heat resistance and oil resistance inherent in the acrylic rubber, and inherent tackiness in the pressure-sensitive adhesive. It is used as needed within a range that does not impair the characteristics such as.

The monomer (B-1) is at least one selected from oxazoline groups, aziridine groups, epoxy groups, hydroxyl groups, carboxyl groups, reactive halogens, amide groups, organosilicon groups and reactive double bond groups. It has two crosslinkable functional groups and a polymerizable double bond group. Monomer (B-1)
Are oxazoline group-containing polymerizable monomers such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline and 2-isopropenyl-2-oxazoline; methacryloylaziridine, methacrylic acid −
Aziridine group-containing polymerizable monomers such as 2-aziridinylethyl; epoxy group-containing vinyl monomers such as allyl glycidyl ether, glycidyl methacrylate and 2-methylglycidyl methacrylate; 2-hydroxyethyl methacrylate; Hydroxyl group-containing polymerizable monomers such as 2-hydroxypropyl methacrylate, monoesters of methacrylic acid and polypropylene glycol or polyethylene glycol, adducts of lactones and 2-hydroxyethyl methacrylate; methacrylic acid, itaconic acid Such unsaturated monocarboxylic acids (excluding acrylic acid)
And carboxyl group-containing vinyl monomers such as salts thereof, unsaturated dicarboxylic acids such as crotonic acid, maleic acid, and fumaric acid, and half-esterified products thereof; and reactivity such as 2-chloroethyl vinyl ether and monochlorovinyl acetate. Halogen-containing vinyl monomer; amide group-containing vinyl monomer such as methacrylamide, N-methylol methacrylamide, N-methoxymethyl methacrylamide, N-butoxymethyl methacrylamide; vinyl trimethoxysilane, γ-methacryloxypropyl Organosilicon group-containing unsaturated monomers such as trimethoxysilane, allyltriethoxysilane, trimethoxysilylpropylallylamine, 2-methacryloxyethoxytrimethoxysilane; ethylidene norbornene, piperylene, isoprene, pentadiene Emissions, vinylcyclohexene, chloroprene, butadiene, methyl-butadiene, cyclopentadiene, and the like can be illustrated diene monomers such as methyl cyclopentadiene, these at least one is used.

The monomer (B-2) does not have a crosslinkable functional group as described above. Specific examples of the monomer (B-2) include aromatic vinyl monomers such as styrene, vinyltoluene, α-methylstyrene, vinylnaphthalene, and halogenated styrene; acrylonitrile; methacrylonitrile; vinyl acetate; Vinylidene chloride; methacrylic esters of alicyclic alcohols such as cyclohexyl methacrylate; methacrylic esters of aromatic alcohols such as benzyl methacrylate; methacrylic esters such as alkyl methacrylate and alkoxyalkyl methacrylate. And at least one of them is used.

In the present invention, a small amount of an additive other than the polymerizable monomer component, for example, a solvent, which does not substantially affect the bulk polymerization may be added. However, at the time of bulk polymerization, it is necessary that the polymerization system be substantially free of general radical polymerization initiators, so-called azo compounds, peroxides and the like. Here, the term "substantially not containing a polymerization initiator" means that the polymerization initiator is not contained at all, or the polymerization initiator is used in an amount smaller than the amount in which mercaptan does not perform the above-mentioned role and a sudden reaction occurs. Says to include. When a general amount of the radical polymerization initiator is used, rapid heat generation occurs during the polymerization and the reaction runs away, so that it is not possible to carry out stable polymerization up to a high polymerization rate of more than 80%. Even if the polymerization can be controlled within the range, the produced polymer will have a large molecular weight distribution. In contrast, in the present invention, such a phenomenon does not occur.

In the present invention, the bulk polymerization reaction can be carried out using a conventionally known polymerization apparatus. For example, a complete mixing type reactor such as a tank type reactor or a kneader equipped with stirring blades of various shapes, a piston flow type reactor having a driving unit such as an extruder, or a drive for stirring a liquid by an obstacle such as a static mixer. And a piston flow type reactor having no part. By using these devices alone or in combination of two or more, bulk polymerization can be performed batchwise or continuously. In particular, the production method of the present invention is characterized in that the reaction is sufficiently mild that bulk polymerization can be performed using a large-capacity tank reactor having a small cooling surface area per volume. The stirring conditions of the reaction mixture during the bulk polymerization according to the present invention can be set in the same manner as in the case of ordinary bulk polymerization.

The polymerization temperature is preferably from 60 to 200 ° C.
00-150 degreeC is more preferable. If the temperature is lower than 60 ° C., the polymerization is slow, which is not industrially practical. If the temperature is higher than 200 ° C., the polymerization rate becomes too fast and control becomes difficult. According to the present invention, a monomer component comprising at least the monomer (A) of the acrylic acid monomer (A) and the other monomer (B) is subjected to bulk polymerization to achieve a high polymerization rate or polymerization. Polymerization can be performed up to a rate of 100% to obtain a high molecular weight acrylic polymer. From the viewpoint of productivity, even when volatile components are removed from the reaction solution under reduced pressure after the bulk polymerization, the polymerization rate is preferably increased to 60% or more, more preferably to 80% or more. In order to produce high-strength high-molecular-weight acrylic polymers for acrylic rubber and high-removable high-pressure acrylic polymers for pressure-sensitive adhesives, it is necessary to obtain polymers with high molecular weight and small molecular weight distribution Therefore, it is preferable to stop the polymerization at a polymerization rate of 60 to 90% and remove volatile components.

The resulting high molecular weight acrylic polymer is obtained by directly removing the reaction solution from the reactor when the polymerization rate reaches 100%, and when the polymerization is stopped in the middle, the volatile component is removed from the reaction solution. Is removed under reduced pressure. Thus, the high molecular weight acrylic polymer obtained by the production method of the present invention has a molecular weight distribution (Mw / Mn) of 1.5 to 7 in terms of polystyrene equivalent molecular weight, depending on the monomer composition. Number average molecular weight is 10.0
It is 00 to 4,000,000, and an acrylic polymer having an arbitrary high molecular weight can be safely and stably obtained by changing the type or amount of the mercaptan and the polymerization temperature. The polymer has at least one of an acrylic acid-based monomer unit (a) derived from the monomer (A) and another monomer unit (b) derived from the monomer (B). It comprises a body unit (a) and has a structure in which these monomer units are regularly or irregularly bonded. The monomer unit (a) is
A crosslinkable acrylic acid-based monomer unit (a-1) having a crosslinkable functional group derived from the monomer (A-1), and a crosslinkable functional group derived from the monomer (A-2) It is at least one of the non-crosslinkable acrylic acid-based monomer units (a-2) not having. The monomer unit (B) is a monomer unit (b) having a crosslinkable functional group derived from the monomer (B-1).
-1) and at least one of other monomer units (b-2) having no crosslinkable functional group derived from the monomer (B-2). The high molecular weight acrylic polymer obtained in the present invention includes a homopolymer of an acrylic acid monomer.

The obtained high molecular weight acrylic polymer can be used in all applications where conventional acrylic polymers are used, such as acrylic rubber, pressure-sensitive adhesives, sealing agents, vibration damping agents,
It is effectively used for asphalt additives and resin modifiers. The high-molecular-weight acrylic polymer, the high-molecular-weight acrylic polymer for acrylic rubber, and the high-molecular-weight acrylic polymer for a pressure-sensitive adhesive of the present invention are manufactured by the above-described high-molecular-weight acrylic polymer of the present invention. Although it can be obtained effectively by a method, it is not limited to this method and can also be obtained by other methods.

[0039]

The acrylic polymer of the present invention is obtained by bulk polymerization , has a structure of CH ₂ ＣＨCHCO—, and has an oxazoline structure.
Phosphorus group, aziridine group, epoxy group, hydroxyl group,
Carboxyl group, reactive halogen, amide group and organic
At least one crosslinkable functional group selected from silicon groups
Containing at least 51% by weight of a monomer unit (a) which may be contained
Look, oxazoline group, aziridine group, an epoxy group, hydrate
Roxyl group, carboxyl group, reactive halogen, amide
Selected from a group, an organosilicon group and a reactive double bond group
0.005 to 1.4 mmol of at least one crosslinkable functional group
/ g, having a number average molecular weight of 66,000 to 100
10,000, the weight average molecular weight is 256,000 to 108,000, the glass transition temperature is 0 ° C. or less, and the molecular weight distribution (Mw / Mn) is 5 or less. The amount of components around the average molecular weight is large, and the amount of low molecular weight and high molecular weight substances is smaller than that, and it is excellent in heat resistance, processing workability and fluidity.

The high-molecular-weight acrylic polymer for acrylic rubber of the present invention is the same as the acrylic polymer of the present invention, except that the acrylic monomer unit (a) is 60 to 100% by weight.
Having a crosslinkable functional group of 0.01 to 1.4 mmol / g,
Since the number average molecular weight is 200,000 to 1,000,000 and the molecular weight distribution is 3 or less, the workability and the strength are well balanced, which is suitable for producing excellent acrylic rubber.

The high molecular weight acrylic polymer for a pressure-sensitive adhesive according to the present invention has a number average molecular weight of 10,000 to 500,000 and a glass transition temperature of -30 ° C. or less in the acrylic polymer of the present invention. It has the advantages of excellent cohesion, water resistance, heat resistance, and removability, and is suitable for producing an excellent pressure-sensitive adhesive. According to the production method of the present invention, the crosslinkable monomer having a crosslinkable functional group is used in an amount of 0.05 to 1
0% by weight, based on 100 parts by weight of a monomer component containing an acrylic acid monomer as a main component and 100 parts by weight of the monomer component.
Since a polymerization raw material containing 1 to 1.0 parts by weight of mercaptan and containing substantially no polymerization initiator is subjected to bulk polymerization, rapid heat generation during polymerization is suppressed, and the polymerization rate is moderated. For this reason, bulk polymerization is performed safely and stably up to a high polymerization rate, and a high molecular weight acrylic polymer having a small molecular weight distribution is produced.

[0042]

EXAMPLES Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples.
In the following, “parts by weight” is “parts”, and “% by weight” is “%”.
It was written. (Example α-1) 650 parts of butyl acrylate was placed in a flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a reflux condenser.
650 parts of ethyl acrylate, 100 parts of styrene, 100 parts of glycidyl methacrylate and 6 parts of trimethylolpropane trithioglycolate were charged and stirred. The mixture was heated to 120 ° C. with stirring while gently blowing nitrogen gas into the mixture to perform polymerization. By heating and cooling by raising and lowering the temperature of the oil bath containing the flask, the polymerization proceeded at a constant temperature of 120 ° C., and could be performed safely and stably. After the polymerization was continued for 4 hours, the reaction mixture was cooled. The polymerization rate of the produced acrylic polymer was 91.1%, and the analysis value in terms of polystyrene by gel permeation chromatography (GPC) (measured similarly in the following) was the number average molecular weight (M
n) = 105,000, weight average molecular weight (Mw) = 32.2
Mw / Mn = 3.1. This polymer-containing reaction mixture was continuously supplied to a twin-screw extruder, and devolatilized under reduced pressure while heating at 200 ° C., whereby a 100% polymer could be taken out.

(Comparative Example α-1) Butyl acrylate 650
Parts, 650 parts of ethyl acrylate, 100 parts of styrene, 100 parts of glycidyl methacrylate and 10 parts of azobisisobutyronitrile were dissolved in 1500 parts of ethyl acetate to prepare a raw material mixture. Half of the mixture is placed in a flask equipped with a stirrer, nitrogen inlet tube, dropping funnel, thermometer and reflux condenser, and the mixture is heated to 80 ° C. with stirring while gently blowing nitrogen gas into the mixture. Then, the remaining amount of the mixed solution was added dropwise over 2 hours, and the mixture was aged for 1.5 hours to carry out polymerization. After the polymerization, the reaction mixture was adjusted to a solid content of 30% with ethyl acetate. The obtained acrylic polymer had a very wide molecular weight distribution, with the number average molecular weight (Mn) = 45,000, the weight average molecular weight (Mw) = 385,000, and Mw / Mn = 8.5.

(Comparative Example α-2) Same as Example α-1 except that 0.15 part of lauryl peroxide as a polymerization initiator was charged instead of 6 parts of trimethylolpropane trithioglycolate as a mercaptan. Was carried out, the temperature could not be kept constant during the polymerization for 4 hours, the temperature rose to 160 ° C., and the polymerization could not be carried out stably. This suggests that on an industrial manufacturing scale, there is the danger of explosion due to sudden reactions.

(Comparative Example α-3) The same operation as in Example α-1 was carried out except that 6 parts of mercaptan, trimethylolpropane trithioglycolate, was not used. Increased to 130 ° C., and stable polymerization could not be performed. The obtained polymer was a gel. In this case, the industrial production scale also suggests the danger of explosion due to rapid reaction.

Comparative Example α-4 10 parts of azobiscyclohexanecarbonitrile as a polymerization initiator was charged into the same apparatus and the polymerizable monomer mixture as in Example α-1, while gently blowing nitrogen gas. At 80 ° C. After 1 hour, the temperature could not be kept constant. Therefore, the temperature was continuously taken out from the lower part of the flask at a rate of 1000 parts / hour, and introduced into a KRC kneader (a self-cleaning continuous kneader manufactured by Kurimoto Iron Works). The temperature in the flask was kept constant by dropping a monomer mixture having the same composition as above into the flask at a constant rate. Polymerization was carried out in a KRC kneader for 1.5 hours. However, the temperature at the inlet of the kneader was 80 ° C., whereas the temperature near the outlet was 150 ° C., indicating an increase in the temperature in the kneader. The polymerization rate of the produced acrylic polymer is 9
6.0%, Mn = 21,000, Mw = 225,000,
Mw / Mn = 10.7. It was taken out from this polymer-containing liquid as a 100% polymer in the same manner as in Example α-1. 100 parts of the obtained acrylic polymer was added to 1000 parts of tetrahydrofuran and sufficiently stirred to dissolve, but an insoluble portion was observed, and the solution did not become a homogeneous solution.

That is, as in Comparative Example α-4, when 10 parts of azobiscyclohexanecarbonitrile as a polymerization initiator and 6 parts of trimethylolpropanetrithioglycolate as a mercaptan were charged into a monomer mixture, In order to keep the temperature constant, a low-temperature monomer mixture for dropping must be added dropwise, and the polymerization is proceeding on a delicate balance. A gel component is formed inside.

(Example α-2) An apparatus similar to that of Comparative Example α-4 (combination of a flask-type reactor and a KRC kneader)
It was used. A monomer mixture consisting of 650 parts of butyl acrylate, 650 parts of methoxyethyl acrylate, 170 parts of ethyl acrylate, 30 parts of glycidyl methacrylate and 7.5 parts of 2-mercaptobenzthiazole was charged into the flask, and gently charged with nitrogen gas. The mixture was heated to 120 ° C. while stirring while blowing. When polymerization was continued at the same temperature for 1.5 hours, a polymerization intermediate was continuously taken out from the lower part of the flask at a rate of 1000 parts / hour, introduced into a KRC kneader, and further polymerized at 110 ° C. for 1 hour. The monomer mixture having the same composition as described above was supplied to the flask at a rate of 1000 parts / hour in the same manner as in Comparative Example α-4, and polymerization was continuously performed. During the polymerization, the polymerization could be stably performed. The polymerization rate of the produced high molecular weight acrylic polymer for acrylic rubber (I) was 90.0%, and Mn = 31.
10,000, Mw = 666,000, and Mw / Mn = 2.1. This polymer-containing liquid was continuously supplied to a twin-screw extruder, and devolatilized under reduced pressure while heating at 180 ° C., and was taken out as a 100% polymer.

A method in which the composition of the monomer units constituting the obtained high molecular weight acrylic polymer for acrylic rubber (I) is hydrolyzed, and the resulting alcohol is quantified by gas chromatography. , H-NMR, elemental analysis,
It was measured by measuring the acid value. as a result,
The polymer (I) has a structure composed of 12.4% of ethyl acrylate units, 43.0% of butyl acrylate units, 43.0% of methoxyethyl acrylate units, and 1.6% of glycidyl methacrylate units. Was.

Example α-3 Acrylic rubber was prepared in the same manner as in Example α-2, except that the monomer mixture having the composition shown in Table 1 was used, and the polymerization temperature was changed to 100 ° C. High molecular weight acrylic polymer (II) was obtained as a 100% polymer. The polymerization was mild and stable as in Example α-2.

(Examples α-4 to α-9) The procedure of Example α-3 was repeated except that a monomer mixture having the composition shown in Table 1 was used, and a high molecular weight acrylic polymer for acrylic rubber ( III) to (VIII) were obtained as 100% polymers. The polymerization was mild and stable as in Example α-2. (Comparative Example α-5) 170 parts of ethyl acrylate, 650 parts of butyl acrylate, methoxyethyl 650
, 30 parts of glycidyl methacrylate and 750 parts of a 3% aqueous solution of sodium dodecyl sulfate were shaken and stirred in a dropping funnel to prepare a pre-emulsion.

In a flask equipped with a stirrer, nitrogen inlet tube, dropping funnel, thermometer and reflux condenser, 15
Then, while stirring the solution while maintaining the solution temperature at 40 ° C., the atmosphere was sufficiently replaced with nitrogen. Subsequently, 112.5 parts of the pre-emulsion prepared in advance, potassium persulfate 3
And 10 parts of 2% sodium bisulfite were added to ion-exchanged water in the flask, and polymerization was started at 40 ° C. with stirring. The remaining pre-emulsion was dropped into the flask over 3 hours. After completion of the dropping, the mixture was aged at the same temperature for 1 hour, and then the reaction solution (emulsion) containing the comparative acrylic polymer (I) was cooled. did. During the polymerization, 10 parts of 2% sodium bisulfite was added every 15 minutes, and the liquid temperature was maintained at 40 ° C. The obtained emulsion was poured into a saturated saline solution to salt out the polymer. This was washed with water and dried to obtain a comparative acrylic polymer (I).

(Comparative Example α-6) Ethyl acrylate 170
650 parts of butyl acrylate, 650 parts of methoxyethyl acrylate, 30 parts of glycidyl methacrylate, 2250 parts of ethyl acetate, 6 parts of azobisisobutyronitrile and 3 parts of 2-mercaptoethanol were prepared.

The same apparatus as in Comparative Example α-5 was used. Into a flask whose inside was replaced with nitrogen, 2,000 parts of the previously prepared mixed solution was charged, and the mixed solution was heated to 80 ° C. to initiate polymerization. The remaining mixed solution was dropped into the flask over 2 hours, and after completion of dropping, the mixture was aged at the same temperature for 1 hour, and then the reaction solution (solution) containing the comparative acrylic polymer (II) was cooled. . The polymer-containing solution was continuously supplied to a twin-screw extruder, and devolatilized under reduced pressure while heating at 180 ° C. to take out a comparative acrylic polymer (II) as a 100% polymer.

High molecular weight acrylic polymers (I) to (VIII) for acrylic rubber and comparative polymers (I) and (II)
Number average molecular weight (Mn), weight average molecular weight (Mw),
Table 2 shows the molecular weight distribution (Mw / Mn), the composition of the constituent units, the amount of the crosslinkable functional group, and the glass transition temperature. The acrylic polymer for comparison (I) tried to be dissolved in tetrahydrofuran for molecular weight measurement, but the gelled product (insoluble matter) was large and could not be measured.

The glass transition temperature was determined by Perkin-Elmer (Pe
rkin Elmer) using a differential scanning calorimeter "DSC-7". The amount of the crosslinkable functional group is K
Titration by OH, epoxy group: reverse titration with HCl addition, hydroxyl group: reverse titration with acetic anhydride addition, halogen (chlorine) is measured by elemental analysis, oxazoline and aziridine groups are analyzed by elemental analysis, IR and NMR. All three methods were measured.

[0057]

[Table 1]

[0058]

[Table 2]

Example β-1 40 parts of HAF carbon (carbon black), 1 part of stearic acid and 3 parts of zinc dimethyldithiocarbamate were added to 100 parts of a high molecular weight acrylic polymer for acrylic rubber (I). Mix by open roll. The mixing workability was evaluated according to the following criteria. The obtained mixture is placed in a sheet molding die for 180
After primary vulcanization by pressing at 6 ° C. for 6 minutes, secondary vulcanization was further performed in an oven at 160 ° C. for 6 hours to obtain an acrylic rubber sheet. This moldability was evaluated based on the following criteria.
The physical properties of the obtained sheet were examined, and the results are shown in Table 3. Tensile strength, elongation and 100% modulus are based on JIS
It was measured according to K-6301. The hardness was measured using a durometer (A type). As for the water resistance, the weight increase value after immersing the acrylic rubber sheet cut into a predetermined size in hot water of 80 ° C. for 24 hours was shown as a percentage (water absorption) with respect to the dry weight before immersion. The higher this value, the worse the water resistance. The water resistance was evaluated according to the following criteria. [Mixing workability]…: There is no adhesion to the open roll, and mixing is easy.

…: Attachment to the open roll is recognized at an early stage, but mixing is easy. ×: Adhesion to the open roll was observed until the latter stage, and mixing was difficult. XX: Adhesion to the open roll was observed even after mixing, making it difficult to remove. [Moldability] A: The surface of the obtained sheet is smooth and glossy.

…: The surface of the obtained sheet is smooth and slightly glossy. ×: The surface of the obtained sheet is uneven. XX: There is no fluidity, and a sheet having a uniform thickness cannot be obtained. [Water resistance] A: The water absorption is 5% or less.

…: Water absorption is more than 5% and 10% or less. X: Water absorption is more than 10% and 15% or less. XX: The water absorption is more than 15%. (Examples β-2 to β-8) Crosslinking shown in Table 3 using high molecular weight acrylic polymers for acrylic rubber (II) to (VIII) instead of high molecular weight acrylic polymers for acrylic rubber (I) An acrylic rubber sheet was obtained by repeating the procedure of Example β-1 except for using the agent. The mixing workability, moldability and physical properties of the acrylic rubber sheet were examined in the same manner as described above, and the results are shown in Table 3.

(Comparative Examples β-1, β-2) Comparative acrylic polymers (I) and (II) were used in place of the high molecular weight acrylic polymer (I) for acrylic rubber, and the crosslinking shown in Table 3 was carried out. An acrylic rubber sheet was obtained by repeating the procedure of Example β-1 except for using the agent. The mixing workability, moldability and physical properties of the acrylic rubber sheet were examined in the same manner as described above, and the results are shown in Table 3.

[0064]

[Table 3]

As shown in Table 3, Examples α-2 to α-9
It was found that the polymers (I) to (VIII) obtained in (1) had good mixing workability and moldability, and gave an acrylic rubber excellent in strength and water resistance. The comparative acrylic polymer (I) obtained in Comparative Example α-5 was a rubber having slightly poor moldability, a poor surface condition, and poor water resistance. In the comparative acrylic polymer (II) obtained in Comparative Example α-6, strong adhesion to the roll was observed during the mixing operation, and the rubber was low in strength.

(Examples α-10 to α- 14 ) The procedure of Example α-4 was repeated except that a monomer mixture having the composition shown in Table 4 was used, and a high-molecular weight acrylic polymer for a pressure-sensitive adhesive was used. Combinations (IX) to (XIII) were obtained as 100% polymers. The polymerization was mild and stable as in Example α-2. (Comparative Example α-7) 260 parts of butyl acrylate, 260 parts of ethyl acrylate
Parts, glycidyl methacrylate 12 parts and styrene 68
The parts were mixed to prepare a monomer mixture. 240 parts of this monomer mixture was placed in a flask equipped with a stirrer, nitrogen inlet tube, dropping funnel, thermometer and reflux condenser,
Further, 360 parts of ethyl acetate was added, and the mixture was heated to 85 ° C. with stirring while gently blowing nitrogen gas. Thereto was added 0.96 part of a 40% xylene solution of benzoyl peroxide as a polymerization initiator, and the remaining 360 parts of the monomer mixture and 0.72 part of a 40% xylene solution of benzoyl peroxide were added for 1.5 hours. At a constant rate. After aging for 1 hour, the solid content was diluted to 40% with ethyl acetate and toluene, followed by aging for 3.5 hours to carry out polymerization. Thereafter, the solvent was removed by a vacuum dryer until the weight became constant. The obtained comparative acrylic polymer (III
) Is considered to have been made three-dimensional during drying, but some were insoluble in tetrahydrofuran, and the molecular weight could not be measured.

(Comparative Example α-8) 86 parts of 2-ethylhexyl acrylate, 10 parts of butyl acrylate, 2 parts of hydroxyethyl methacrylate, 2 parts of acrylic acid, 0.1 part of t-dodecyl mercaptan, polyoxyethylene nonylphenyl 11.5 parts of a 26% aqueous solution of sodium ether sulfate and 34.5 parts of ion-exchanged water were shaken and stirred in a dropping funnel to prepare 146.1 parts of a pre-emulsion.

A flask equipped with a stirrer, a nitrogen inlet tube, a dropping funnel, a thermometer and a reflux condenser was charged with ion-exchanged water 3.
8.2 parts were charged, and the mixture was sufficiently purged with nitrogen while stirring while maintaining the liquid temperature at 70 ° C. Subsequently, 1% of the pre-emulsion prepared in advance (ie 1.46)
1 part) and 8 parts of a 5% aqueous potassium persulfate solution were added to initiate polymerization. The remaining pre-emulsion was dropped at a constant rate into the flask over 3 hours, and 15 parts of a 1% aqueous sodium bisulfite solution was equally added at 10-minute intervals during the drop of the pre-emulsion. After completion of the dropwise addition, the mixture was aged for 1 hour to obtain a comparative acrylic polymer (IV). The obtained comparative acrylic polymer (IV) was insoluble in tetrahydrofuran, and its molecular weight could not be measured.

(Comparative Example α-9) Butyl acrylate 570
Parts and 30 parts of acrylic acid were mixed to prepare a monomer mixture. 240 parts of it was taken in a flask equipped with a stirrer, nitrogen introduction tube, dropping funnel, thermometer and reflux condenser,
Further, 375.4 parts of ethyl acetate was added, and the mixture was heated to 85 ° C. with stirring while gently blowing nitrogen gas. Thereto was added 0.96 part of a 40% xylene solution of benzoyl peroxide as a polymerization initiator, and the remaining 360 parts of the monomer mixture and 0.72 part of a 40% xylene solution of benzoyl peroxide were added for 1.5 hours. At a constant rate. After aging for 1 hour, the solid content was diluted to 40% with ethyl acetate and toluene, followed by aging for 3.5 hours to carry out polymerization. The obtained acrylic polymer for comparison (V)
Has a very wide molecular weight distribution, with the number average molecular weight (Mn) = 41,000, the weight average molecular weight (Mw) = 950,000, and Mw / Mn = 23.3.

(Comparative Examples α-10 to α-12) The procedure of Comparative Example α-9 was repeated, except that the monomer solvent mixture having the composition shown in Table 4 was used. ) To (VIII). High molecular weight acrylic polymers (IX) to (XIII) for pressure sensitive adhesives and comparative polymers (II
Compositions of constituent units and number average molecular weights (M) of (I) to (VIII)
n), weight average molecular weight (Mw), molecular weight distribution (Mn / M
Table 5 shows w), the amount of the crosslinkable functional group, and the glass transition temperature.

[0071]

[Table 4]

[0072]

[Table 5]

(Example γ-1) 100 parts of a high molecular weight acrylic polymer (VIII) for a pressure-sensitive adhesive was coated on a 25 μm polyester film by a hot melt roll coater so as to have a dry film thickness of 25 μm. The pressure-sensitive adhesive tape was obtained. (Comparative Example γ-1) Comparative acrylic polymer (III) 10
0 part was coated on a 25 μm polyester film by a hot melt roll coater so as to have a dry film thickness of 25 μm to obtain a pressure-sensitive adhesive tape.

(Comparative Example γ-2) One part of a 25% aqueous zinc oxide dispersion was added to 100 parts of a comparative acrylic polymer (IV).
In addition, the viscosity is 10,000cp with polycarboxylic acid thickener.
The mixture adjusted to s was applied on a 25 μm polyester film with an applicator so as to have a dry film thickness of 25 μm, and heated at 100 ° C. for 2 minutes to obtain a pressure-sensitive adhesive tape.

The pressure-sensitive adhesive properties of these pressure-sensitive adhesive tapes were examined, and the results are shown in Table 6. Ball tack, adhesive strength, high temperature adhesive strength, and holding power were measured in accordance with JIS Z 0237. The temperature rise creep was measured by raising the temperature from 40 ° C. under a holding force of JIS Z 0237 under a condition of 3 ° C./5 minutes under a load of 1 kg. The removability was evaluated based on the following criteria for the state of the adhesive residue on the adherend SUS when the adhesive strength was measured one month after the application. For water resistance, the degree of whitening after immersing the pressure-sensitive adhesive tape in ion-exchanged water for one day was evaluated according to the following criteria.

[Removability]…: no adhesive residue △: partial adhesive residue ×: severe adhesive residue [water resistance] ○: almost no whitening △: partial whitening ×: almost whitening

[0077]

[Table 6]

As shown in Table 6, the high molecular weight acrylic polymer (IX) for the pressure-sensitive adhesive was the comparative acrylic polymer (II).
Compared with I), it was found that creep in temperature rise, that is, heat resistance and removability were excellent with almost the same holding force. In addition, it was found that heat resistance, removability and water resistance were superior to the comparative acrylic polymer (IV) obtained by emulsion polymerization.

(Examples γ-2 to γ- 3 and Comparative Example γ-3) High-molecular-weight acrylic polymers (IX) to (X) for pressure-sensitive adhesives and comparative acrylic polymer (V) are shown in Table. 7 was mixed. Mixability when this compound and the crosslinking agent were mixed with a stirrer was evaluated according to the following criteria. The resulting mixture is
A 5 μm polyester film was coated with an applicator so as to have a dry film thickness of 25 μm, and heated at 100 ° C. for 2 minutes to obtain a pressure-sensitive adhesive tape. The pressure-sensitive adhesive properties of this pressure-sensitive adhesive tape were examined in the same manner as in Example γ-1, and the results are shown in Table 7.

[Mixing Ability] ○: Uniform mixing easily △: Time-consuming but uniform mixing ×: Uniform mixing is difficult

[0081]

[Table 7]

As shown in Table 7, the high-molecular-weight acrylic polymers (IX) to (X) for pressure-sensitive adhesives were more excellent in mixing property than the comparative acrylic polymer (V), and were almost the same. It was found that the holding power was excellent in heat resistance and removability. (Example .gamma. 4, .gamma. 5 and Comparative Examples γ-4, γ-5) sensitive pressure sensitive adhesives for high molecular weight acrylic polymer instead of adhesives for high molecular weight acrylic polymer (IX) ( XI) , (XI
Example γ-2 was carried out using I) and comparative acrylic polymers (VI) and (VII) with the formulation shown in Table 8.
Was repeated to obtain a pressure-sensitive adhesive tape.

(Example γ- 6 and Comparative Example γ-6) Instead of the high-molecular-weight acrylic polymer for pressure-sensitive adhesive (IX), a high-molecular-weight acrylic polymer for pressure-sensitive adhesive (XIII) was prepared. The procedure of Example γ-2 was repeated to obtain a pressure-sensitive adhesive tape, except that the acrylic polymer (VIII) was used and the dry film thickness was set to 60 μm and the double-sided tape specification was used in the composition shown in Table 8. .

The pressure-sensitive adhesive properties of these pressure-sensitive adhesive tapes were examined in the same manner as in Example γ-1. The results are shown in Table 8.

[0085]

[Table 8]

As shown in Table 8, each high molecular weight acrylic polymer for a pressure-sensitive adhesive is superior in mixing property, heat resistance and removability as compared with a comparative acrylic polymer having almost the same composition. I understand.

[0087]

The high-molecular-weight acrylic polymer of the present invention does not contain a surfactant, has a limited polymer composition,
Since it has excellent heat resistance, processing workability and fluidity, it is suitable for applications such as acrylic rubber, pressure-sensitive adhesives, sealing agents, vibration dampers, resin modifiers and asphalt additives.

The high molecular weight acrylic polymer for acrylic rubber of the present invention has a good balance between workability and strength.
When this is used, an acrylic rubber having excellent moldability, strength and water resistance and low adhesiveness can be produced. Also,
When the high molecular weight acrylic polymer for a pressure-sensitive adhesive of the present invention is used, a pressure-sensitive adhesive excellent in cohesive force, water resistance and heat resistance and free of adhesive residue upon re-peeling can be produced.

According to the production method of the present invention, a high-molecular-weight acrylic polymer containing no emulsifier or dispersant and having a small molecular weight distribution can be obtained safely and stably with high productivity on an industrial scale. When copolymerization is performed, a high molecular weight acrylic copolymer having a desired composition can be obtained because the composition of the monomer mixture is not limited. In the conventional bulk polymerization of acrylic polymers, a special apparatus has been proposed to control the rapid heat generation. However, according to the production method of the present invention, a high-molecular-weight acrylic polymer can be easily used in a general reaction apparatus. The acid-based monomer can be produced by bulk polymerization, which is industrially very significant in terms of safety.

Since the high molecular weight acrylic polymer obtained by the production method of the present invention has a small molecular weight distribution, for example, the high molecular weight component may exhibit the required performance, and the low molecular weight component may cause a decrease in the performance. Very useful in applications.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // C09J 133/02 C09J 133/02 133/14 133/14 (72) Inventor Kenji Minami No. 5 Nishimitabicho, Suita-shi, Osaka No. 8 Nippon Shokubai Central Research Laboratory Co., Ltd. (72) Inventor Masuji Izumibayashi 5-8 Nishiburi-cho, Suita City, Osaka Prefecture No. 8 Nippon Shokubai Central Research Laboratory Co., Ltd. No. 5-8 Onarimachi Nippon Shokubai Suita Works, Ltd. (56) References JP-A-57-115478 (JP, A) JP-A-63-37112 (JP, A) JP-A-63-66211 (JP, A) A) Patent 2582510 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 220/00-220/70

Claims (5)

(57) [Claims] 1. A high molecular weight acrylic polymer obtained by bulk polymerization, having a structure of CH ₂ 2CHCO—.
Oxazoline group, aziridine group, epoxy group, hydride
Roxyl group, carboxyl group, reactive halogen, amide
At least one frame selected from a group consisting of
Have the bridge functional group which may monomer units (a) 51
Wherein wt% or more, oxazoline group, aziridine group, Epo
Xyl group, hydroxyl group, carboxyl group, reactive halo
Gen, amide group, organosilicon group and reactive double bond group
At least one crosslinkable functional group selected from the group consisting of 0.005
Having a structure having a molecular weight of mmol1.4 mmol / g and a number average molecular weight of 6.6.
1,000,000, a weight average molecular weight from 256,000 to 108.1
10,000, glass transition temperature of 0 ° C. or less and molecular weight distribution (Mw /
Mn) a high molecular weight acrylic polymer having a molecular weight of 5 or less. 2. A high molecular weight acrylic polymer for acrylic rubber obtained by bulk polymerization, wherein CH ₂ ＣＨCHCO
Having an oxazoline group, an aziridine group,
Xyl group, hydroxyl group, carboxyl group, reactive halo
Gen, amide group and organosilicon group
Least one crosslinkable functional group which 60 to 100 wt% saw including a good monomer units (a) have a, oxazoline group, A
Dilysine group, epoxy group, hydroxyl group, carboxy
Group, reactive halogen, amide group, organosilicon group and
It has a structure having at least one crosslinkable functional group selected from reactive double bond groups of 0.01 to 1.4 mmol / g, a number average molecular weight of 200,000 to 1,000,000, and a weight average molecular weight of 256,000.
A high molecular weight acrylic polymer for acrylic rubber, having a glass transition temperature of 0 ° C. or lower and a molecular weight distribution (Mw / Mn) of 3 or lower. 3. Oxygen having a structure of CH ₂ ＣＨCHCO—
Sazoline group, aziridine group, epoxy group, hydroxyl
Group, carboxyl group, reactive halogen, amide group and
At least one crosslinkable function selected from organosilicon groups
The monomer unit (a) which may have a group is 60 to 100
% By weight only contains, oxazoline group, aziridine group, an epoxy
Group, hydroxyl group, carboxyl group, reactive halogen
Group, amide group, organosilicon group and reactive double bond group
At least one crosslinkable functional group selected from 0.01 to
It has a structure having 1.4 mmol / g and has a number average molecular weight of 200,000-
1,000,000, weight-average molecular weight 256,000-108,000,
Glass transition temperature of 0 ° C or less and molecular weight distribution (Mw / M
n) an acrylic rubber having a molecular weight of 3 or less and containing a high-molecular-weight acrylic polymer obtained by bulk polymerization as a main component; 4. A high molecular weight acrylic polymer for a pressure-sensitive adhesive obtained by bulk polymerization, wherein CH ₂ ＣＨCHCO—
Having an oxazoline group, an aziridine group, and an epoxy group.
Si, hydroxyl, carboxyl, reactive halogen
At least one selected from an amide group, an amide group and an organosilicon group.
Contains at least 51% by weight of a monomer unit (a) which may have one crosslinkable functional group, and contains an oxazoline group,
Gin group, epoxy group, hydroxyl group, carboxyl
Group, reactive halogen, amide group, organosilicon group and anti-
It has a structure having 0.005 to 1.4 mmol / g of at least one crosslinkable functional group selected from reactive double bond groups , and has a number average molecular weight of 66,000 to 500,000 and a weight average molecular weight of 256,000.
A high-molecular-weight acrylic polymer for a pressure-sensitive adhesive , which has a glass transition temperature of -30 ° C. or lower and a molecular weight distribution (Mw / Mn) of 5 or lower. 5. Oxygen having a structure of CH ₂ ＣＨCHCO—
Sazoline group, aziridine group, epoxy group, hydroxyl
Group, carboxyl group, reactive halogen, amide group and
At least one crosslinkable function selected from organosilicon groups
Not less than 51% by weight of a monomer unit (a) which may have a group ;
Including above , oxazoline group, aziridine group, epoxy group,
Hydroxyl group, carboxyl group, reactive halogen,
Selected from mid groups, organosilicon groups and reactive double bond groups
At least one crosslinkable functional group from 0.005 to 1.4
has a structure with mmol / g, number average molecular weight from 66,000 to 50
10,000, weight average molecular weight 256,000 to 108,000, glass transition temperature -30 ° C or lower, and molecular weight distribution (Mw / Mn)
5 or less, a pressure-sensitive adhesive comprising a high molecular weight acrylic polymer obtained by bulk polymerization as an adhesive component.