JPH05163322A - Methacrylate resin composition - Google Patents

Abstract

PURPOSE:To obtain a methacrylate resin composition excellent in solvent resistance and vibration-damping performance by mixing an unsaturated monomer composed mainly of an alkyl methacrylate, a crosslinkable monomer and a specific block copolymer. CONSTITUTION:The title composition comprises 30-97 pts.wt. unsaturated monomer which is composed mainly of an alkyl methacrylate and may contain the polymer thereof, 0-60 pts.wt. crosslinkable monomer, and 3-70 pts.wt. block copolymer having a number-average molecular weight of 30,000-300,000 and consisting of a block C1, which is made from at least one aromatic vinyl monomer and has a number-average molecular weight of 2,500-40,000, and a block C2, which is made from isoprene or an isoprene-butadiene mixture, contains 30% or more of the 3,4-bonds and 1,2-bonds and has a number-average molecular weight of 10,000-200,000, or a hydrogenated derivative thereof.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a methacrylic resin composition having vibration damping performance.

[0002]

2. Description of the Related Art A gel polymer obtained by partially crosslinking a mixture of an unsaturated monomer mainly composed of alkyl methacrylate and a crosslinkable monomer is used as a molding material or an adhesive agent, and is resistant to solvent and heat. Of excellent workability and workability
0-202128, JP-A-62-1705, JP-A-2-294311, and JP-A-2-294.
No. 376, etc.

In recent years, the quietness of home electric appliances, office automation equipment, etc. has become a selling point in accordance with the consumer's preference for luxury goods, and the vibration damping performance is increasingly required for the materials used for these. Came.

However, the cured product obtained by polymerizing the above mixture is insufficient in terms of vibration damping property, and for this purpose, a method of attaching or applying a vibration damping material has been adopted. However, there is a drawback that the cost or the number of steps is increased.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have found that a mixture of an unsaturated monomer containing an alkyl methacrylate as a main component, a crosslinkable monomer and a styrene-isoprene block copolymer having a specific structure. As a result, they have found that a new methacrylic resin composition having a new function of vibration damping, which has never been obtained, can be obtained, and the present invention has been completed.

[0006]

According to the present invention, the above-mentioned problems are solved by the following: (a) 30 to 97 parts by weight of an unsaturated monomer which is mainly composed of an alkyl methacrylate and may contain a polymer thereof, (b) 0-60 parts by weight of crosslinkable monomer, and (c)
A block (A) having at least one vinyl aromatic monomer and a number average molecular weight of 2,500 to 40,000 and isoprene or an isoprene-butadiene mixture, and the content of 3,4 bonds and 1,2 bonds is 30% or more. The number average molecular weight of the block (B) having a number average molecular weight of 10,000 to 200,000 is 30,000 to 3
Block copolymer of 00000 or its hydrogenated product 3 to
This is solved by a methacrylic resin composition containing 70 parts by weight.

The methacrylic resin composition of the present invention is used as a molded product, an adhesive or a coating material, and it is possible to reduce the vibration of the used part.

Further, the methacrylic resin composition of the present invention undergoes co-crosslinking with the unsaturated monomer, the cross-linking agent and the block copolymer during polymerization and curing, so that the solubility in the solvent is lowered and the solvent resistance is reduced. At the same time, it has the characteristics that it exhibits excellent heat resistance due to its low fluidity at high temperatures.

The unsaturated monomer which is the main component of the component (a) of the present invention and which may contain the polymer thereof is an unsaturated monomer which may be copolymerized with the alkyl methacrylate alone or the alkyl methacrylate. , Β-ethylenically unsaturated monomer mixture, or a solution containing these polymers in the monomer alone or in the monomer mixture.

The alkyl methacrylate is not particularly limited and includes, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, dicyclohexyl methacrylate. Examples include pentenyl methacrylate. The alkyl methacrylate is preferably used alone or as a mixture of two or more kinds from the above-mentioned monomers, but a lower alkyl methacrylate having 1 to 4 carbon atoms is preferable, and methyl methacrylate is particularly preferable.

Examples of other α, β-ethylenically unsaturated monomers which can be copolymerized are methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate and tert. -Butyl acrylate, 2-
Alkyl acrylates such as ethylhexyl acrylate, cyclohexyl acrylate, lauryl acrylate and dicyclopentenyl acrylate, alkoxyalkyl acrylates such as methoxyethyl acrylate, alkoxy polyethylene glycol methacrylates such as methoxydiethylene glycol methacrylate, alkoxyalkyl methacrylates such as n-butoxyethyl methacrylate, 2- Hydroxyalkyl acrylates such as hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 3-hydroxybutyl acrylate, 2
-Hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 2-hydroxy-3-chloropropyl methacrylate, and other hydroxyalkyl methacrylates, acrylic acid, neodymium acrylate , Acrylates such as lead acrylate, neodymium methacrylate, methacrylates such as lead methacrylate, vinyl chloride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, styrene, α-methylstyrene, vinyltoluene, anhydrous Examples include maleic acid and crosslinkable monomers.

When the unsaturated monomer mainly composed of alkyl methacrylate contains these polymers, the concentration of the polymer is not more than 40 parts by weight, preferably 30 in consideration of the viscosity of the solution. It is preferable that the amount is not more than parts by weight.

The crosslinkable monomer which is the component (b) of the present invention has at least two (meth) acryloyl groups in the molecule and has 10 or less carbon atoms between the (meth) acryloyl groups. It is preferable to have, for example, the following formula (1)
~ (3) MA-O- ( CH 2) n -O-MA ... (1) [ where n is an integer of 3 to 6, MA represents a methacryloyl group. ] (M) A-O- CH 2 -C (R 1) (R 2) -CH (R 3) -O- (M) A ... (2) [ wherein R ₁ is a hydrogen atom, CH ₃ group, Represents a C ₂ H ₅ group or a CH ₂ OH group, R ₂ represents a hydrogen atom or a CH ₃ group,
CH ₂ OCOC (R ₄ ) ═CH ₂ group (R ₄ represents a hydrogen atom or a CH ₃ group) or a CH ₂ OH group, R
₃ represents a hydrogen atom or a CH ₃ group, R ₁ , R ₂ and R ₃ are not hydrogen atoms at the same time, and (M) A represents a methacryloyl group or an acryloyl group. _{] (M) AO (CH 2} CH 2 O) n (M) A ... (3) [ where n is 1 or 2 and represents the (M) A is a methacryloyl group or an acryloyl group. ] It is an unsaturated monomer represented by. Specifically, 1,3-propylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol methacrylate, 1,3-butylene glycol dimethacrylate, dimethylolethane dimethacrylate, 1,1- Dimethylolpropane dimethacrylate, 2,2-dimethylolpropane dimethacrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane dimethacrylate, ethylene Examples thereof include glycol di (meth) acrylate and diethylene glycol di (meth) acrylate. Among these, the monomer represented by the above formula (2) is preferable. From the viewpoint of fluidity, 2,2-dimethylolpropane methacrylate (neopentyl glycol dimethacrylate) is particularly preferable.

The amount of these crosslinkable monomers used is 0 to 60.
Parts by weight, preferably 2 to 50 parts by weight. 60
If it exceeds the amount by weight, the cured product finally obtained becomes brittle, which is not preferable.

The following are used as the block copolymer which is the component (c) of the present invention. The number average molecular weight of the vinyl aromatic block (A) is in the range of 2500-40000. When the molecular weight is less than 2,500, the adhesive strength becomes insufficient when a product obtained by mixing and polymerizing an unsaturated monomer and a crosslinkable monomer is used as an adhesive. Molecular weight is 4
If it exceeds 0000, the viscosity when mixed with the monomer becomes too high, and the polymerization and curing will not be successful, which is not preferable.

The proportion of the vinyl aromatic block (A) in the block copolymer is 5% by weight to 50% by weight.
Those in the range of are preferably used. If this ratio is less than 5%, the mechanical properties of the block copolymer itself may be insufficient when used as an adhesive, and the resulting cured product may not have sufficient adhesive performance. On the contrary, if it exceeds 50%, mixing with the monomer may not be successful,
In addition, the effect of improving the vibration damping performance also decreases.

As the second component of the block copolymer used in the present invention, isoprene or isoprene-butadiene is preferably used in combination. By using the monomers of isoprene and butadiene, the glass transition temperature (Tg) of this block can be easily controlled, and the economy is excellent. When isoprene-butadiene is used in combination, the form of copolymerization of the block (B) may be random, block or tapered.

In the present invention, the block (B) of the block copolymer has a content of 3,4 bonds and 1,2 bonds of 30%.
It is necessary to be above. 3,4 bonds and 1,2
When the bond content is lower than the above range, the effect of imparting vibration damping performance to a cured product obtained by polymerizing a mixture of an unsaturated monomer and a crosslinkable monomer cannot be exhibited. The number average molecular weight of the block (B) used is in the range of 10,000 to 200,000. When the molecular weight is smaller than the above range, the cured product may not have sufficient adhesiveness, which is not preferable. On the other hand, if it is too large, the viscosity when mixed with the unsaturated monomer and the crosslinkable monomer becomes too high, and the fluidity deteriorates, which is not preferable.

Further, the number average molecular weight of the block copolymer must be in the range of 30,000 to 300,000. If the molecular weight is less than 30,000, mechanical properties such as strength and elongation at break of the block copolymer itself are deteriorated and the performance of the finally obtained cured product is deteriorated, which is not preferable. Further, when it exceeds 300,000, the viscosity when mixed with the unsaturated monomer and the crosslinkable monomer becomes too high, and the fluidity is deteriorated, which is not preferable in some cases. From this viewpoint, the molecular weight of the block copolymer is more preferably 80.
It is preferable to be in the range of 000 to 250,000.

The block morphology of the block copolymer of the present invention can be represented by A (BA) n or (AB) n. Here, A is a block composed of an aromatic vinyl monomer, B is a block composed of isoprene or isoprene-butadiene, and n is an integer of 1 or more. Of these, the one in the form of ABA is most preferably used.

In this block of isoprene or isoprene-butadiene, some of the carbon-carbon double bonds in the block are hydrogenated if necessary. The hydrogenation rate in this case is determined according to the required level of heat resistance and weather resistance, but is usually 50% or more, preferably 70% or more,
80% when higher heat resistance and weather resistance are required
The above hydrogenation rate is used. If the hydrogenation rate is less than 50%, the effect of improving heat resistance and weather resistance cannot be obtained.

The block copolymer of the present invention can be obtained by the following various methods.

First, the block copolymer is produced by a method of (a) sequentially polymerizing an aromatic vinyl compound, isoprene or isoprene-butadiene with an alkyllithium compound as an initiator, (b) an aromatic vinyl compound, and then isoprene or isoprene. -A method of polymerizing butadiene and coupling it with a coupling agent, or a method of sequentially polymerizing isoprene or isoprene-butadiene and then an aromatic vinyl compound using (c) a dilithium compound as an initiator.

Examples of the alkyl lithium compound include alkyl compounds having an alkyl residue having 1 to 10 carbon atoms, and particularly methyl lithium, ethyl lithium,
Pentyl lithium and butyl lithium are preferred. Dichloromethane, dibromomethane, dichloroethane, dibromoethane, dibromobenzene and the like are used as the coupling agent. Examples of the dilithium compound include naphthalenedilithium and dilithiohexylbenzene. The amount used is determined by the molecular weight to be calculated, but with respect to 100 parts by weight of all the monomers used for the polymerization,
About 0.1 to 0.2 parts by weight of each initiator and about 0.04 to 0.8 parts by weight of the coupling agent are used.

A Lewis base is used as a cocatalyst in the polymerization of isoprene or isoprene-butadiene in order to keep the Tg of the block comprising isoprene or isoprene-butadiene in the range of -40 to 20 ° C. Examples of Lewis bases include ethers such as dimethyl ether, diethyl ether and tetrahydrofuran, glycol ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, triethylamine, N, N, N ′, N′-tetramethylethylenediamine (TMEDA), N- Examples thereof include amine compounds such as methylmorpholine. The amount of these Lewis bases used is about 0.
It is used in the range of 1 to 1000 times.

A solvent is preferably used in the polymerization for easy control. As the solvent, an organic solvent inert to the polymerization catalyst is used. Especially carbon number 6-12
Of these, aliphatic, alicyclic and aromatic hydrocarbons are preferably used. Examples thereof include hexane, heptane, cyclohexane, methylcyclohexane, benzene and the like.

The polymerization is 0 to 8 in any polymerization method.
It is carried out in the temperature range of 0 ° C. for 0.5 to 50 hours.

The obtained block copolymer is hydrogenated by a known method if necessary. A method of reacting molecular hydrogen with a known hydrogenation catalyst in a state of being the same as or different from the solvent used in the polymerization, and in a state of being dissolved in a hydrogenation reaction, a solvent inert to the hydrogenation catalyst is preferable. Used. Examples of the catalyst used include Raney nickel, a heterogeneous catalyst such as Pt, Pd, Ru, Rh, and Ni supported on a simple substance such as carbon, alumina, diatomaceous earth, or a transition metal and an alkylaluminum compound. ,
A Ziegler type catalyst or the like composed of a combination of alkyl lithium compounds and the like is used. In the reaction, hydrogen pressure is normal pressure to 200 kg / cm ² , reaction temperature is normal temperature to 250 ° C.,
The reaction time is 0.1 to 100 hours.

The hydrogenation rate is determined by the required level of physical properties, but when heat resistance and weather resistance are important, 5
It is preferable to hydrogenate to 0% or more, preferably 70% or more.

The block copolymer after the reaction is solidified with methanol or the like and then heated or dried under reduced pressure, or the reaction liquid is poured into boiling water to azeotropically remove the solvent, and then heated or dried under reduced pressure. It is obtained by doing.

The amount of the block copolymer used is 3 to 70 parts by weight, preferably 5 to 60 parts by weight. If the amount used is less than 3 parts by weight, the damping property of the finally obtained cured product cannot be sufficiently obtained, and conversely, if it exceeds 70 parts by weight, the polymerization rate decreases and the curing time becomes long, which is preferable. Absent.

The methacrylic resin composition of the present invention is usually polymerized and cured using a polymerization initiator. Radical polymerization initiators such as azo compounds and peroxides are preferably used as the initiator. The amount used is 0. 0, based on the total amount of the unsaturated monomer, the crosslinkable monomer and the block copolymer.
It is used in the range of 002 to 10 parts by weight, preferably 0.005 to 5 parts by weight.

When the methacrylic resin composition of the present invention is used as a molded product, a mixture of an unsaturated monomer, a cross-linking agent and a block copolymer is pre-heated to form a partially cross-linked gel polymer to obtain a rod. , Blocks, pellets, or the like, or after adding the unsaturated monomer containing alkyl methacrylate as a main component to the gel-like material or a crushed product of the gel-like material, and after substantially kneading the composition, A method of molding with a commonly used molding machine, or a method of injecting a composition containing the gelled material or an unsaturated monomer having an alkyl methacrylate as a main component into a mold and curing it by heating is used. When used as a coating material or an adhesive, a partially crosslinked gel polymer is applied to the coating or adherend as a solution and cured under heating, or as in the case of using as a molded article. Alternatively, a composition containing an unsaturated monomer containing alkyl methacrylate as a main component is formed into a sheet and then attached to a cover or an adherend, or a rod, a block or a pellet, and then a cover or an adherend. A method of spraying on and curing under heating is used. Furthermore, a solution of the mixture is formed into a thread, a woven fabric,
A method of impregnating a fiber such as a non-woven fabric or paper, pasting this on an adhesive portion, heating and curing it, and adhering may also be used.

The composition of the present invention is used by adding various additives as required. As an example, 20 parts by weight to 2
50 parts by weight of carbon black, silica, calcium carbonate, mica, graphite, wollastonite and the like reinforcing agents, fillers, etc., 0.01 to 5 parts by weight of antioxidants, ultraviolet absorbers and the like can be mentioned. Of these, fillers having a large aspect ratio, such as mica, graphite and wollastonite, are particularly preferably used because they improve the vibration damping performance. If these fillers are added, the amount should be 2
By using 0 parts by weight or more, more preferably 40 parts by weight or more, it becomes possible to exhibit a high level of vibration damping performance.

The methacrylic resin composition of the present invention is used as a molded product in the fields where heat resistance, solvent resistance and vibration damping are required, and also as a covering material for plastic, metal, wood, fiber, paper or the like. It is also preferably used as an adhesive.

[0036]

The present invention will be described in more detail with reference to the following examples.

Each measured value in the examples was determined by the following method.

The molecular weight was determined by GPC.

Tg was measured by DSC.

The hydrogenation rate was calculated from the ratio of the iodine values of the block copolymer before and after the hydrogenation reaction.

The peak temperature of tan δ was determined by measuring the viscoelastic spectrum with Rheovibron (manufactured by Orientec).

As an index of damping performance, 0, 25, 40 ° C.
The value of tan δ at was calculated. The larger this value is, the better the vibration damping property is.

The solvent resistance test was carried out by placing a panel in which toluene, ethanol and isopropanol had been dipped on the surface of the cured product, leaving it in a closed system for 8 hours, then wiping the solvent contact surface and observing the change in the surface condition visually. I observed. Reference Example Drying and nitrogen-substituted pressure resistant reactor, cyclohexane as a solvent, n-butyllithium as a polymerization catalyst, TMEDA as a Lewis base as a cocatalyst, and styrene monomer, isoprene monomer, and styrene monomer were added in this order for polymerization. By doing so, block copolymers (I) and (II) having an ABA structure were obtained. Further, the obtained copolymer was subjected to hydrogen reaction in cyclohexane at a hydrogen pressure of 20 kg / cm ² using Pd-C as a catalyst to obtain hydrogenated block copolymers (III) and (IV). The molecular characteristics of these block copolymers and their hydrogenated products are shown in Table 1. Examples 1 to 4 70 parts by weight of methyl methacrylate monomer, 10 parts by weight of neopentyl glycol dimethacrylate, block copolymer or hydrogenated block copolymer 2 obtained in Reference Example
0 parts by weight, 2,2'-azobis (4-methoxy-2,4
-Dimethylvaleronitrile) 0.01 parts by weight and 2,
0.5 parts by weight of 2-bis (t-butylperoxy) butane was mixed and dissolved, poured into a cell assembled with two glass plates, and polymerized at 60 ° C. for 2 hours to obtain a partially crosslinked gel polymer. It was The obtained partially crosslinked gel polymer was pulverized with a pulverizer to have a maximum particle size of 2 mm or less. The crushed product was put into a mold having a thickness of 10 mm and kept at a pressure of 30 kg / cm ² at 130 ° C. for 10 minutes to obtain a molded product.

The tan δ of the obtained molded product was measured to evaluate the vibration damping performance. Further, as a solvent resistance test, the surface of the molded product was brought into contact with an organic solvent such as toluene or alcohol, and a change in appearance was observed. Examples 5 to 9 Polymerized by the same formulation as in Examples 1 to 4, crushed crushed products were sandwiched between two acrylic plates having a thickness of 3 mm, a length of 240 mm and a width of 190 mm, at 130 ° C. for 10 minutes, and a pressure of 30 kg / cm
^An adhesive product was obtained by keeping the pressure at ² . The adhesive strength of the obtained adhesive product was measured by a tensile test method (JIS K6851), and the fracture surface was visually observed. Comparative Example 1 70 parts by weight of methyl methacrylate monomer, 30 parts by weight of neopentyl glycol dimethacrylate, 0.01 parts by weight of 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) and 2,2-bis. Example 1 was prepared by mixing and dissolving 0.5 part by weight of (t-butylperoxy) butane.
Molded products were obtained by the same method as described above.

Further, an adhesive article was prepared by the same method as in Examples 5 to 8 and the adhesive strength was measured.

Table 2 shows the measurement results of Examples 1 to 9 and Comparative Examples 1 and 2. From this result, it is possible to finally mix a mixture of unsaturated monomer mainly composed of alkyl methacrylate and a crosslinkable monomer with a styrene-len block copolymer having a specific molecular structure and its hydrogenated product. It can be seen that the obtained cured product has excellent vibration damping performance as well as solvent resistance. Also, it is found that the adhesive has sufficient adhesive strength.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

The composition of the present invention comprising an unsaturated monomer mainly comprising alkyl methacrylate, a crosslinkable monomer, a styrene-isoprene block copolymer having a specific molecular structure, and a hydrogenated product thereof, By heat curing, it can be used as a new acrylic resin having excellent solvent resistance and excellent vibration damping performance. Further, even when the partially crosslinked gel polymer is used as an adhesive, it has sufficient adhesive strength.

Claims (1)

[Claims] 1. An unsaturated monomer 30 which comprises (a) an alkyl methacrylate as a main component and may contain a polymer thereof.
97 parts by weight, (b) 0 to 60 parts by weight of a crosslinkable monomer, and (c) a block (A) having at least one vinyl aromatic monomer and a number average molecular weight of 2500 to 40,000, and isoprene or isoprene- It is composed of a butadiene mixture and has a number-average molecular weight of 10,000 to 2000 with 3,4 and 1,2 bond contents of 30% or more.
The number average molecular weight composed of block (B) of 00 is 3
A methacrylic resin composition comprising 30,000 to 300,000 block copolymer or 3 to 70 parts by weight of a hydrogenated product thereof.