JP2678068B2 - ABS resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to an ABS resin composition having excellent vibration damping performance.

2. Description of the Related Art In recent years, plastic materials have been generally used as casings, interiors and exteriors of various equipment including office equipment, audio equipment and household electric appliances. Of these, the acrylonitrile-butadiene-styrene terpolymer ABS resin is widely used because it has good processability, good electrical properties, and excellent surface gloss. In applications of office equipment such as copiers and printers in which this product is used, reduction of noise and vibration generated by them is an important issue. Furthermore, household appliances are becoming larger due to changes in lifestyles, and low vibration and low noise of appliances with vibration, such as refrigerators, washing machines, and vacuum cleaners, are also important in terms of quiet performance as a product. It is one.

[Problems to be solved by the invention]

Polymer materials are originally advantageous materials in terms of suppressing the generation of vibration and noise compared to metal materials, but they are not satisfactory from the viewpoint of vibration and noise near room temperature where various devices are used. There wasn't. The main object of the present invention is to improve the vibration damping performance of a general-purpose ABS resin as a material for various devices at around room temperature.

[Means for Solving the Problems]

According to the present invention, the above-mentioned problems are (a) from 97 to 50 parts by weight of ABS resin, and (b) from a block (A) composed of a vinyl aromatic monomer having a number average molecular weight of 2500 to 40,000 and isoprene or isoprene-butadiene. The number average molecular weight is 10,000 to 200,000 and the content of 3,4 and 1,2 bonds is 40.
% Or more and having a number average molecular weight of 30 composed of a block (B) having a main dispersion peak of tan δ at 0 ° C. or higher.
This is achieved by a composition containing 3 to 50 parts by weight of a block copolymer of 000 to 300,000 or a hydrogenated product thereof. The composition can be used as a material in which generation of vibration and noise is reduced without impairing the moldability of the ABS resin. Hereinafter, the present invention will be described in more detail. ABS resin used in the present invention is composed of terpolymer of acrylonitrile, butadiene, styrene, butadiene alone or styrene, rubber polymerized with acrylonitrile (PBR, SBR, NBR) and styrene, acrylonitrile copolymer It is produced by a polymer blending method in which styrene and acrylonitrile are graft-copolymerized with polybutadiene. The ratio of butadiene component in ABS resin is 5-40
%, And the composition of the resin component is in the range of 70 to 80% and 30 to 20% of styrene and acrylonitrile, respectively. The first component of the block copolymer which is the other component used in the present invention is an aromatic vinyl monomer, for example, styrene, α-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 3-methyl Styrene, 4-propylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene and the like are preferred, with styrene being most preferred. The number average molecular weight of the vinyl aromatic block (A) is 2500-
It is in the range of 40000. When the molecular weight is less than 2500, the performance as a composition decreases, and when it exceeds 40,000, the melt viscosity becomes too high, and the composition with the ABS resin does not work well, and a composition having sufficient performance cannot be obtained. Further, the proportion of the vinyl aromatic block (A) in the block copolymer is preferably in the range of 5% by weight to 50% by weight. If this ratio is less than 5%, the mechanical properties of the block copolymer will be insufficient, and conversely 50%.
If it exceeds the above range, the viscosity becomes extremely high, so that processing such as mixing becomes difficult and the vibration damping performance deteriorates. Further, isoprene or an isoprene-butadiene mixture is preferably used as the second component of the block copolymer used in the present invention. When other monomers are used, for example, when butadiene is used alone,
Even if the 1,2 bond content is increased, the temperature at which the vibration damping performance is exhibited is less than 0 ° C, and the function at the temperature actually used cannot be obtained, so that it has little practical significance. In the case of isoprene, by considering the content of 3,4 bond and 1,2 bond of the present invention (hereinafter, these may be collectively referred to as vinyl bond content), practical use at a temperature of approximately 0 ° C or around 50 ° C is achieved. The vibration damping performance can be exhibited in a wide temperature range, and a wide range of applications can be achieved, which is extremely useful in practice. Isoprene
When using a butadiene mixture, the proportion of isoprene
If it is 40% or more, it exhibits vibration damping performance at 0 ° C or more. When the isoprene-butadiene mixture is used, the form of the block (B) may be random, block or tapered. The block copolymer (B) of the present invention has a content of 3,4 bonds and 1,2 bonds of 40% or more (may be 100%). If the vinyl bond content is less than 40%, sufficient vibration damping performance cannot be obtained in a normal operating temperature range, which is not preferable. It can also be obtained by measuring the viscoelasticity of the block copolymer.
It is necessary that the temperature of the peak of the main dispersion of tan δ (loss tangent) is 0 ° C. or higher. Even when there is a peak only at a temperature lower than 0 ° C., sufficient vibration damping performance cannot be obtained in a normal temperature range. When the amount of vinyl bonds in the isoprene block is 100%, the tan δ absorption temperature is about 60 ° C, so the upper limit is about 60 ° C. The number average molecular weight of the block (B) is 10,000 to 20,000.
A range of 0 is used. When the number average molecular weight of the block (B) is smaller than the above range, the elastic properties are not impaired, which is not preferable. On the other hand, if it is too large, the fluidity becomes poor, which is not preferable. The number average molecular weight of the obtained block copolymer is 30,000 to 3
Must be in the range of 00000. If the molecular weight is less than 30,000, the mechanical properties such as strength at break and elongation at break of the block copolymer itself are reduced, and when the composition is used as a composition, the strength is undesirably reduced. On the other hand, if it exceeds 300,000, the processability is deteriorated, the mixing with the ABS resin is not successful, and a composition having sufficient performance cannot be obtained. From this point, the molecular weight of the block copolymer is preferably in the range of 80,000 to 250,000. The block morphology of the block copolymer is A (BA) n, (A
B) 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 ABA form is most preferably used. In the present invention, the block copolymer is obtained by the following various methods. First, the block copolymer is produced by (a) a method of sequentially polymerizing an aromatic vinyl compound, isoprene or isoprene-butadiene using an alkyllithium compound as an initiator, (b) an aromatic vinyl compound, and then isoprene or isoprene-butadiene. A method of polymerizing and coupling it with a coupling agent, a method of sequentially polymerizing isoprene or isoprene-butadiene and then an aromatic vinyl compound using (c) a dilithium compound as an initiator can be mentioned. Examples of the alkyl lithium compound include an alkyl compound having 1 to 10 carbon atoms in the alkyl residue,
Particularly, methyl lithium, ethyl lithium, pentyl lithium and butyl lithium are preferred. As the coupling agent, dichloromethane, dibromomethane, dichloroethane, dibromoethane, dibromobenzene and the like are used. Examples of the dilithium compound include naphthalenedilithium and dilithiohexylbenzene. The amount used is determined by the molecular weight to be determined, but generally about 0.0 parts by weight of initiator based on 100 parts by weight of all monomers used for polymerization.
It is used in the range of 1 to 0.2 parts by weight and the coupling agent in the range of 0.04 to 0.8 parts by weight. As a microstructure of the isoprene or isoprene-butadiene part, vinyl bonds are 40% or more and ta
A Lewis base is used as a cocatalyst in the polymerization of isoprene or isoprene-butadiene mixture in order to have a peak of the main dispersion of nδ. Examples of Lewis bases include dimethyl ether, diethyl ether, ethers such as tetrahydrofuran, ethylene glycol dimethyl ether, glycol ethers such as diethylene glycol dimethyl ether, triethylamine, N, N,
N ', N'-Tetramethylethylenediamine (TMEDA), N-
Examples thereof include amine compounds such as methylmorpholine.
These Lewis bases are used in an amount of about 0.1 to 1000 times the mole number of lithium in the polymerization catalyst. In the polymerization, a solvent is preferably used for easy control. As the solvent, an organic solvent inert to the polymerization catalyst is used. Particularly, aliphatic, alicyclic and aromatic hydrocarbons having 6 to 12 carbon atoms are preferably used. Examples include hexane, heptane, cyclohexane, methylcyclohexane, benzene, and the like. The polymerization is carried out in any of the polymerization methods at a temperature in the range of 0 to 80 ° C. for 0.5 to 50 hours. By subjecting the obtained block copolymer to a hydrogenation reaction, if necessary, a part or all of the carbon-carbon double bonds in the block composed of isoprene or isoprene-butadiene mixture are hydrogenated. For the hydrogenation reaction, a method of reacting hydrogen in a molecular state with a known hydrogenation catalyst in a state of being dissolved in a solvent inert to the reaction and the catalyst is preferably used. As the catalyst used, Raney nickel, or Pt, Pd, Ru, Rh, Ni and other metals such as carbon, alumina, heterogeneous catalyst such as those supported on a simple substance such as diatomaceous earth, or transition metal and Alkyl aluminum compound,
A Ziegler type catalyst or the like composed of a combination of alkyl lithium compounds and the like is used. The reaction is carried out at a hydrogen pressure of normal pressure to 200 kg / cm ² , a reaction temperature of normal temperature to 250 ° C., and a reaction time of 0.1 to 100 hours. After the reaction, the block copolymer may be obtained by coagulating the reaction solution with methanol or the like and then heating or drying under reduced pressure, or by pouring the reaction solution into boiling water to azeotropically remove the solvent and then heating or drying under reduced pressure. Is obtained by The hydrogenation rate is determined by the required level of physical properties, but when heat resistance and weather resistance are important, it is preferable to hydrogenate to 50% or more, preferably 70% or more. The composition of the present invention is mixed with ABS resin in an amount of 97 to 50 parts by weight and the block copolymer in an amount of 3 to 50 parts by weight. When the ratio of the block copolymer is less than this, the vibration damping performance of the resulting composition is insufficient, and when it is more,
The composition softens and loses its properties as a plastic.
S resin is not suitable for its intended purpose and is not preferable. The composition of the present invention contains an ABS resin and a block copolymer as essential components, but various additives are blended and used as necessary. Examples thereof include 20 parts by weight to 250 parts by weight of carbon black, silica, calcium carbonate, reinforcing agents such as mica, fillers, etc., and 0.01 to 5 parts by weight of antioxidant,
Examples thereof include UV absorbers. Of these, mica is particularly preferably used because it improves vibration damping performance. When mica is added, it is possible to exhibit higher vibration damping performance by using at least 20 parts by weight, more preferably at least 40 parts by weight. Further, other polymers may be blended and used as long as the gist of the present invention is not impaired. Examples are polyethylene, polystyrene, atactic polypropylene, polybutene, polyvinyl chloride, EP.
R, styrene-conjugated diene block copolymers, hydrogenated products thereof, ethylene-vinyl acetate copolymers and the like. The blend ratio of these polymers is preferably about 30% by weight or less. The composition of the present invention, by kneading and molding using a kneader, an extruder, an injection molding machine, etc., office equipment, audio equipment, household appliances, including the housing of various equipment,
It is preferably used for inner and outer materials, automobile inner and outer materials, bumpers and the like.

【Example】

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, each measured value in an Example was calculated | required by the following method. The molecular weight was determined by GPC. Microstructure measured NMR spectrum, 4.8 ppm, 5.8 ppm
The content of 3,4 bonds and 1,2 bonds was calculated from the ratio of the peaks of 3,4 bonds and 1,2 bonds and the peak of 5.3 bonds at 1.4 bonds. 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 a viscoelastic spectrum with Leo Vibron (manufactured by Orientec). The value of tan δ at 25 ° C was obtained as an index of damping performance. The larger this value is, the better the vibration damping property is. Reference Example A styrene monomer, an isoprene monomer, and a styrene monomer were sequentially added and polymerized in a pressure-resistant reactor dried and replaced with nitrogen, using cyclohexane as a solvent, n-butyllithium as a polymerization catalyst, and TMEDA as a vinylating agent.
The obtained ABA type copolymer in cyclohexane,
Hydrogenation reaction was carried out at a hydrogen pressure of 20 kg / cm ² using Pd-C as a hydrogenation catalyst to obtain block copolymers (I), (II) and (III) having the molecular characteristics shown in Table 1. . Kneading the block copolymers obtained in Examples 1 to 6 and Comparative Examples 1 and 2 and the ABS resin (Sumitomo Nogatac Co., Ltd.) at 170 ° C. with a Brabender according to the formulation shown in Table 2. To prepare a composition. The obtained composition was press-molded at 200 ° C. to form a 2 mm sheet, and tan δ at 25 ° C. was measured. For comparison, the ABS resin alone or a mixture of the ABS resin and a styrene-isoprene-styrene block copolymer having a small vinyl bond (SIS, TR-1107, vinyl bond amount 12%; manufactured by Shell Chemical Co.) are also shown. The tan δ was measured. Table 2 shows the results. From these results, it is understood that the composition of the present invention has an excellent vibration damping effect.

【The invention's effect】

The composition of the present invention, which is characterized by combining an ABS resin with a specific molecular structure, can be used as a material with reduced vibration and noise generation without impairing the moldability of the ABS resin. Excellent vibration damping performance, especially near room temperature.

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Claims (1)

(57) [Claims] 1. (a) 97 to 50 parts by weight of ABS resin, and (b)
A block (A) composed of a vinyl aromatic monomer having a number average molecular weight of 2,500 to 40,000 and isoprene or isoprene-butadiene, and a number average molecular weight of 10,000 to 20,000.
0, the content of 3,4 bonds and 1,2 bonds is 40% or more,
A number average molecular weight of 30,000 to 300,000, which is composed of a block (B) having a peak of main dispersion of tan δ at 0 ° C. or higher.
An ABS resin composition comprising 3 to 50 parts by weight of a block copolymer of the above or a hydrogenated product thereof.