JPS6225144A - Styrene resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having excellent mechanical strength and moldability without deteriorating the heat-resistance of the base resin, by compounding a styrene resin with a specific amount of a petroleum resin produced by polymerizing 1,3-pentadiene as main monomer. CONSTITUTION:A styrene resin is compounded with 0.001-0.5wt%, preferably 0.01-0.4wt% petroleum resin obtained by polymerizing 1,3-pentadiene as main monomer and having an MW/MN ratio of 2-4.5 and an MN of >=1,300 wherein MW is weight-average molecular weight reduced to polystyrene and MN is number-average molecular weight reduced to polystyrene.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a styrenic resin composition having excellent mechanical strength and molding performance.

(Prior art) General-use polystyrene resins or impact-resistant polystyrene resins have traditionally been used in food containers such as seasoning containers, frozen confectionery containers, lactic acid bacteria drink containers, housings for radios and televisions, VTR cassettes σ) half, It is used in a wide range of fields, including weak components such as compact cassette halves and cases. Most of these are molded using injection molding machines, but depending on the application, the molded products have complex shapes and are made of resin. requires better moldability, and
When using a container or case, there are cases where the container or case accidentally falls onto the floor, so mechanical strength is also important for practical purposes.

In order to improve the mechanical strength of impact-resistant polystyrene resin, efforts have been made to increase the content of reinforcing rubber and adjust the particle size of the rubber dispersed in the resin. Molded products do not have sufficient strength. In addition, increasing the molecular adhesion of impact-resistant polystyrene resins and general-use polystyrene resins is also a means of improving mechanical strength, but at the same time, moldability decreases, which is undesirable. For this purpose, it is a known method to create a composition in which a styrene-butadiene block copolymer is kneaded, but it has the disadvantage of reducing heat resistance, and furthermore, when added to general polystyrene resin, It inhibits the transparency, which is a characteristic of general-purpose polystyrene resin, and is undesirable (・.

On the other hand, various methods are known as methods for improving molding processability.
Lowering the molecular weight of the styrene polymer is a means of improving moldability, but it also reduces mechanical strength, which is not preferable.

In addition, using butyl stearate or OT plasticizers before white mineral oil is a method to improve moldability, but heat resistance decreases, rigidity is poor, and partial whitening occurs during mold release during injection molding. There are drawbacks such as:

(Problems to be Solved by the Invention) An object of the present invention is to eliminate such drawbacks of the prior art and provide a styrenic resin composition that does not impair heat resistance and has excellent mechanical strength and moldability. With the goal.

(Means for Solving the Problems) As a result of intensive research, the present inventor found that 1.
3 Petroleum resin obtained by polymerization using pentadiene as the main monomer
．． It has been discovered that a styrene resin composition containing 65% by weight of 001-05 has excellent mechanical strength and moldability, and the present invention has been completed.

In the present invention, the styrenic resin is not only a general-use polystyrene side resin obtained by polymerizing a styrene monomer, but also a copolymer containing a styrene monomer as a main component and other copolymerizable vinyl monomers. Impact-resistant polystyrene resin obtained by polymerizing a styrenic monomer or a styrenic monomer and other copolymerizable monomers in the presence of a polymer or a rubbery polymer. includes. Here, the styrenic monomer refers to one or more of styrene, α-methylstyrene, tertiary-butylstyrene, p-methylstyrene, etc.
5. Examples of other vinyl monomers that can be copolymerized with the monomer include acrylonitrile, methacrylic acid esters, acrylic esters, and N-substituted maleimides. Rubbery polymers include butadiene, etc. , conjugated 1,3 diene polymers such as inobreno, chlorobrene, styrene-butadiene copolymer rubber, butyl rubber, and ethylene-propylene terpolymer (EPDM), and one or more of these may be used. When the styrenic monomer is copolymerized with other vinyl monomers or rubber-like substances, the styrenic monomer is at least 5% of the copolymer.
It is necessary to occupy 0 weight jt% or more. Further, when a rubbery polymer is used, the amount used is usually 1 to 15 parts by weight of the styrenic resin. If it exceeds this range, the viscosity of the styrenic monomer solution of the rubbery polymer will increase, and the stirring power of the polymerization apparatus will become extremely large, which is undesirable from the viewpoint of the apparatus.

The petroleum resin conveniently used in the present invention is a monomer mainly composed of 1 and 3 pentadiene obtained by further refining the cracked oil fraction produced as a by-product from an ethylene plant that produces ethylene, propylene, etc. by cranking petroleum. V) obtained by polymerization as In general, petroleum resins are often polymerized without isolating the diolefins and monoolefins contained in the above-mentioned by-product cracked oil fraction, but among these, aromatic resins are produced by copolymerizing styrene, pinijanotluene, α-methylstyrene, indene, etc. family petroleum resin (commonly known as 5 C9 petroleum resin)
is not preferable because it does not have the effect of improving mechanical strength, which is the objective of the present invention. The petroleum resin capable of achieving the purpose of the present invention must be a combination of 1.3 pentadiene as a main component as described above, but a part of it may also be an aromatic monomer such as styrene. It is possible.

The styrene-based fat composition of the present invention contains 0.0% petroleum oil obtained by polymerizing 1.3pentadiene as the main monomer.
0.001 to 0.05% by weight, preferably 0.01 to 0.04% by weight. If the amount added is less than 0.001% by weight, the effect of improving mechanical strength will be poor;
Even if it is added in an amount exceeding 100%, the strength improving effect will not be increased, and on the contrary, heat resistance and rigidity will be impaired, which is not preferable.

The petroleum resin used in the present invention has a molecular weight measured by gel permeation chromatography (GPC), and the ratio of the weight average molecular weight Mw in terms of polystyrene to the number average molecular weight M9 in terms of polystyrene is Mw//MN.
It is desirable that the value of is between 2.0 and 4.5. Mw/M
When N is narrow (less than 2.0 σ) or wide (more than 4.5), mechanical strength is poorly developed. Further, it is also desirable that the number average molecular weight MN in terms of polystyrene is 1300 or more. If it is less than 1300, the strength will not be developed much.

The method for producing the styrenic A1 fat composition of the present invention includes:
There are two methods: mechanical mixing, such as kneading the petroleum oil into styrene resin using an extruder, and mixing during the polymerization process to obtain a styrene polymer. Preferably, general purpose polystyrene resin or impact-resistant It is preferable to use an addition method in which the polystyrene resin is dissolved and mixed in the styrene monomer before polymerization. The polymerization method is not particularly limited, and bulk, suspension, or bulk-suspension polymerization methods are preferred, but are not limited to these.

In the styrenic side layer composition according to the present invention, antioxidants, lubricants, mold release agents, fillers, etc. can be added as necessary during processing, and within the range known to those skilled in the art. Regardless of the amount added, the effects of the present invention are not impaired in any way.

(Example) Next, the present invention will be specifically explained by using Examples and Comparative Examples. However, the present invention is not limited to these examples.

Example 1 A petroleum resin (manufactured by Nippon Zeon Co., Ltd., product name:
40 kg of a styrene bath solution in which Finton A-100'') 1601 had been dissolved in advance was added. To this, dicumyl peroxide 207 and tert dodecyl mercaptan 20
1 and stirred at 180 rpm. After replacing the inside of the can with nitrogen gas, it was sealed and the temperature was raised.

After polymerizing at 110°C for 4 hours, it was cooled, and then the capacity was 100°C.
50 Kq of pure water and 3502 Kq of sodium dodecylpenozene sulfone modified sodium phosphate 3502 were added to an autoclave, and while stirring at 160 rpm, 40 Kq of 2,2-di-tert-butylperoxybutane was added.
Then, 40 kg of the prepolymerization solution to which 80 r of tert-butyl peroxybenzoate had been added was added, and after purging with nitrogen, the reactor was sealed and the temperature was raised. Temperature: 105℃ for 2 hours 115℃ for 3 hours, 1
Polymerization was carried out at 35° C. for 3 hours and cooled.

Polymer beads were obtained after neutralization, dehydration, and drying according to conventional methods, and then pelletized using an extruder to obtain an impact-resistant styrenic resin composition.

The properties and physical property measurement results of Finton A-100 used in this example are shown in Table 1.

Example 2 The same procedure as in Example 1 was carried out except that the petroleum resin was used as 1602 (Finton R-100j manufactured by Nippon Zeon Co., Ltd.), and IW! A high-impact styrenic resin composition was obtained. Table 1 shows the properties of Finton R-100 used in this example and the results of measuring the physical properties of the composition.

Example 3 The same procedure as in Example 1 was carried out, except that 209% of the petroleum resin Finton A-1 was used, and an impact-resistant styrene-based cutting resin composition was prepared.

The physical property measurement results are shown in Table 1.

Comparative Example 1 The same procedure as in Example 1 was repeated except that the petroleum resin was not added to obtain impact-resistant styrene cut resin. The results of physical property measurements are shown in the first column.

Comparative Example 2 In Example 1, instead of Finton A-100, the aromatic oil field side (Mitsui Petrochemical Co., Ltd.'s "Vetlozin #1") was used instead of Finton A-100.
An impact-resistant styrenic resin composition was obtained in the same manner as in Example 1, except that 20J) was used. Table 1 shows the properties of Bell Rosin #120 used in this example and the results of measuring the physical properties of the composition.

Example 4 A petroleum resin (a product manufactured by Nippon Zeon Co., Ltd.) obtained by polymerizing an impact-resistant styrene resin (11L, trade name manufactured by Keikagaku Co., Ltd. [Denka Styrol H1-R-6J]) with 1,3 pentadiene as the main monomer. Quinton G-100J (0.05% by weight) was mixed and pelletized using an extruder to obtain an impact-resistant styrenic resin composition.
The properties of No. 100 and the results of measuring the physical properties of the composition are shown in the first layer.

Example 5 0.3% by weight of petroleum [Uit Quinton A-100] was mixed with general-purpose polystyrene resin ('N! Kaka Seikagaku Co., Ltd. trade name: Ncastyrol MT, 2''), and the mixture was made into pellets using an extruder. A styrene resin composition was obtained.

The physical property measurement results are shown in Table 1.

Comparative Example 3 Table 1 shows the results of measuring the physical properties in Example 5 without adding petroleum resin.

The molecular weight distribution of Stone y II + resin was determined by GPC [Toyo a Renso 11
The molecular weight was determined in terms of standard polystyrene using a data processor CF)-8000 manufactured by Toyo Soda.

Solvent: Tetrahydrofuran ('rHF) Column: 2 G3000H columns manufactured by Toyo D-Soku Thermostatic bath Temperature: 40°C Detector: Differential refractometer The method for measuring each physical property value is as follows: Tensile strength: According to JIS K-6871.

Izod impact strength: According to JIS K-6871.

Drill strength: A load of 1000 with a wire tip of 5R and a screw diameter of 141φ at the center of a 2N thick 12Lyn square plate made by injection molding.
r, the height at which no cracking occurs when a 70 (1,5 tH') hammer is dropped, and i=x*.

The molding machine is Niigata Iron Works g! Molding was performed using a 2-ounce in-line screw injection molding machine 5N-51B at a molding temperature of 230°C. It should be noted that the fJy-shaped product formed by injection molding is easily susceptible to directionality, and even when it breaks due to external force, it is likely to break in the direction of the molding flow σ. In this respect, since the directionality of the plow drop strength is the easiest to find, in the present invention, the plow drop strength is adopted as an expression that suits the actual situation.

Melt flow rate: According to JIS K-6870.

Vicat softening point: According to JIS K-6870.

Patent applicant: Tsuyuki Kagaku Kogyo Co., Ltd. Procedural amendment August 2, 1985

Claims (3)

[Claims] (1) A styrenic resin composition containing 0.001 to 0.5% by weight of a petroleum resin obtained by polymerizing 1,3 pentadiene as a main monomer. (2) Polystyrene equivalent weight average molecular weight of petroleum resin @M
The styrene according to claim 1, wherein the ratio @M@_W/@M@_N of @_W and the polystyrene equivalent number average molecular weight @M@_N is 2.0 to 4.5. based resin composition. (3) Polystyrene equivalent number average molecular weight of petroleum resin @M@
The styrenic resin composition according to claim 1 or 2, wherein _N is 1300 or more.