KR100210978B1 - The process for preparing thermoplastic resins having good whiteness - Google Patents

Abstract

The present invention relates to a method for producing a thermoplastic resin.

An object of the present invention is to provide a thermoplastic resin excellent in whiteness in a range that does not impair the general physical properties of the ABS resin.

The present invention 1) one or two or more monomer mixtures and emulsifiers selected from aromatic vinyl monomers and unsaturated nitrile monomers in a continuous dosing method by grafting the SAN copolymer in the presence of butadiene-based rubber latex copolymer 1 step reaction in which a part of the distribution was added to the reactor by adding a molecular weight regulator, a polymerization initiator, and ion-exchanged water, and a first graft was performed by adding an redox catalyst at a reactor temperature of 40 ° C to 65 ° C, and 2 ) After dispensing the remaining portion of the primary graft latex into a pre-emulsion state, it is continuously added over 1 hour to 4 hours to make the graft polymerization uniform and increase the polymer at a constant rate so that the polymerization rate is 90-95%. 2) the reaction, and 3) unreacted by adding a redox catalyst when the polymerization rate of the two-stage reaction reaches 90-95%. It is characterized by allowing most of the monomer to participate in the polymerization.

Description

Manufacturing method of thermoplastic resin excellent in whiteness

The present invention relates to a method for producing a thermoplastic resin excellent in whiteness.

Acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as ARBS resin) is a mechanical balance with high stiffness and impact resistance as well as excellent workability and chemical resistance, and is suitable for electric appliances, electronics, automobile parts, and office equipment. It is widely used.

The ABS resin can be obtained by adding a monomer such as styrene, acrylonitrile or methyl methacrylate in the presence of rubber latex prepared by emulsion polymerization, and then carrying out polymerization by adding a radical generating initiator. Generally, general-purpose resins having excellent impact strength include high-impact polystyrene and high-impact polyvinyl chloride resin. Among them, high-impact polystyrene (HIPS) has lower impact strength and gloss than ABS resin, but has excellent whiteness and is used in various applications. . ABS resins, however, have excellent physical balance and are difficult to produce a variety of products to meet the needs of consumers due to the reduction in whiteness due to the emulsion polymerization process and the monomers used.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a thermoplastic resin having excellent whiteness in a range that does not impair the general physical properties of the ABS resin. In order to achieve the above object, as a result, proper selection of the type of redox catalyst, adjustment of the input temperature and the timing of the input lead to uniform polymerization, thereby improving whiteness, and continuous monomer input method and polymerization initiator through a multi-step reaction. It was found that the thermoplastic resin having excellent whiteness which improves the physical properties of the rubber latex by increasing the polymerization rate at a constant rate by adding to

That is, the present invention, in the graft of the SAN copolymer to the rubber latex particles, in the presence of butadiene-based rubber latex, one or two or more monomer mixtures selected from aromatic vinyl monomers and unsaturated nitrile monomers, emulsifiers, polymerization initiators, molecular weight regulators, and oxidation A part of the distribution was introduced into the reactor by the distribution addition of the reduction catalyst and the ion exchanged water, and a first stage reaction in which the redox catalyst was added to the primary kraft at a reactor internal temperature of 40-65 ° C., and the first kraft latex was aromatic. One or two or more monomer mixtures selected from vinyl monomers and unsaturated nitrile monomers, and partially distributed residues of the first kraft reaction in emulsifiers, polymerization initiators, molecular weight modifiers, and ion-exchanged water were made into a pre-emulsion for 1 hour. In rubber grafts by continuous feeding over 4 hours The second stage reaction to homogeneously and to increase the polymerization rate at a constant rate so that the polymerization rate is 90-95%, and when the polymerization rate of the two-stage reaction reaches 90-95%, the redox catalyst is By adding most of the unreacted monomers to the polymerization.

Hereinafter, the present invention will be described in detail.

The method of grafting the SAN copolymer to the rubber latex particles is based on the gel content of 70-85% by weight, and the aromatic vinyl monomer and unsaturated nitrile compound in the presence of 30-65 parts by weight of butadiene rubber latex (based on solids) of 0.25-0.30 microns in average particle diameter. It is preferable to copolymerize 70-35 parts by weight of the monomer mixture of 100 parts by weight of the total amount of the butadiene rubber latex and the monomer mixture.

When the amount of the rubber latex is used in a smaller amount than the above range, the impact reduction amount of the resin is lowered, and the use of the large amount of the rubber latex is difficult to recover the fine powder during solidification and drying of the graft latex.

Monomers usable in the present invention include aromatic vinyl monomers such as alpha methylstyrene, styrene, alpha chlorostyrene, vinyltoluene, divinylbenzene, pt-butylstyrene, 2,4-dimethylstyrene, acrylonitrile, methacrylonitrile, and the like. Unsaturated nitrile monomers. Among these, preferably, one or two or more copolymers selected from styrene, acrylonitrile and methacrylonitrile are preferable. Its use amount is 0-12.25 parts by weight of the first stage reaction (0-9.18 parts by weight of styrene, 0-3.07 parts by weight of acrylonitrile), 70-22.75 parts by weight of the second stage of reaction (52.5-17.06 parts of styrene, 17.5 parts of acrylonitrile). -5.69 parts by weight). The use of the first and second graft monomers in a smaller amount than the above range reduces the impact resistance of the resin and the hardness of the resin.

As the emulsifier used in the present invention, a conventional emulsion polymerization reaction may be used. Examples thereof include sodium laurate, sodium oleate, potassium oleate, sodium lauryl sulphate, potassium mimisulfate, and sodium naphthalene sulfonate. And sodium isopropyl, naphthalene sulfonate, and the like. Among them, one or two or more emulsifiers selected from potassium oleate, sodium oleate, and sodium lauryl sulphate are preferable.

Their amount is 0.03-2.0 parts by weight in the one-step reaction and 0.1-3.5 parts by weight in the two-step reaction. If the amount of emulsifier used in the first and second stages is smaller than the above range, the coagulant in the latex is excessively used, and the amount of the emulsifier is used to reduce the impact due to the excessive generation of the non-craft polymer.

Examples of the polymerization initiator usable in the present invention include fat-soluble initiators such as alkali metal peroxide, cumene hydroperoxide, benzoyl peroxide, t-butyl peroxide and dicumyl peroxide, and water-soluble initiators such as potassium persulfate and ammonium persulfate. have. Among them, one or two or more initiators selected from fat-soluble initiators such as cumene hydroperoxide and benzoyl peroxide are preferable. These amounts are 0.03-0.25 parts by weight in the one-step reaction and 0.08-0.45 parts by weight in the two-step reaction.

Redox catalysts usable in the present invention include redox catalysts such as metal salts such as ferrous sulfate, sodium parophosphate, sodium formaldehyde sulfoxylate, ethylenediaminetetraacetic acid, textose, sodium hydroxide and sodium pyrophosphate. Among them, a combination method using ferrous sulfate, sodium fordium aldehyde sulfoxylate and ethylenediaminetetraacetic acid is preferable.

These amounts are preferably 0.001-0.35 parts by weight for each redox agent in the one-step reaction, 0.001-0.25 parts by weight for each redox agent at the end of the two-step reaction.

As a molecular weight regulator which can be used for this invention, it is preferable to use molecular weight regulators, such as a C8-18 mercaptan or an organohalogen compound. These amounts are 0.05-0.35 parts by weight in the one-step reaction and 0.08-0.48 parts by weight in the two-step reaction. If the amount of the first and second stages is used in a larger amount than the above range, the molecular weight drops sharply, thereby reducing the tensile strength.

The latex prepared as described above was obtained as a powder through a solidification and drying process, then mixed with a styrene-acrylonitrile copolymer (SAN) having good compatibility with the ABS resin, followed by an extrusion and injection process to obtain an ABS resin having excellent whiteness. Manufacture.

Embodiments of the present invention are as follows.

Example 1

50 parts by weight of butadiene rubber latex having an average particle diameter of 0.28 microns (hereinafter, by weight based on solids), 150 parts by weight of ion-exchanged water, 0.8 parts by weight of potassium oleate, 7.5 parts by weight of styrene, 2.5 parts by weight of acrylonitrile, and 0.2 weights of dodecylmercaptan After the addition, the mixture was stirred at 45 ° C. for 20 minutes, and then 0.15 parts by weight of silica hydrochloride was added to raise the temperature to 60 ° C. When the temperature of the mixture reached 60 ° C., 0.08 parts by weight of ferrous sulfate, 0.15 parts by weight of sodium fordium aldehyde sulfoxylate, and 0.10 parts by weight of disodium ethylenediaminetetraacetic acid were added to proceed the polymerization for 1 hour to complete the one-step polymerization.

After completion of the one-step polymerization, 30.0 parts by weight of styrene, 10.0 parts by weight of acrylonitrile, 2.0 parts by weight of potassium oleate, 0.4 parts by weight of cumene hydroxide peroxide, 0.35 parts by weight of dodecylmercaptan, and 15 parts by weight of ion-exchanged water were stirred. Put it in a container as possible and make it into a pre-emulsion state, and continuously dosing for 3 hours to proceed the second kraft reaction, and when the polymerization rate of the two-stage reaction reaches 95%, 0.005 parts by weight of ferrous sulfate, sodium formium sulphylsil 0.1 weight part of rate and 0.08 weight part of ethylenediaminetetraacetic acid disodium were added to terminate the polymerization after 1 hour of polymerization.

At this time, the polymerization time was 4 hours at 70 ℃.

Example 2

0.15, 0.1 parts by weight of sodium formaldehyde sulfoxylate and 0.1, 0.08 parts by weight of ethylenediamidetraacetic acid disodium, 0.15 parts of secondary text, 0.1 parts by weight of secondary and 0.1 parts by weight of pyrophosphate The same procedure as in Example 1 was carried out except that the sodium primary was replaced with 0.1 and secondary 0.08 parts by weight.

Example 3

The same procedure as in Example 1 was carried out except that 0.4 parts by weight of cumene hydroperoxide was temporarily added 30 minutes after the start of continuous preemulsion in the second step of the second grafting reaction.

Example 4

The same procedure as in Example 1 was carried out except that 15 parts by weight of ion-exchanged water and 2.0 parts by weight of potassium oleate were added without the addition of the pre-emulsion continuous addition method and added with the monomer continuous addition method.

Comparative Example 1

50 parts by weight of butadiene rubber latex having an average particle diameter of 0.28 microns, 150 parts by weight of ion-exchanged water, 1.5 parts by weight of potassium oleate, 18.75 parts by weight of styrene, 6.25 parts by weight of acrylonitrile, and 0.2 parts by weight of dodecylmercaptan into the reactor and at 45 ° C. After stirring for 20 minutes, 0.15 parts by weight of cumene hydroperoxide was added thereto, and the temperature was raised to 60 ° C. When the temperature of the mixture reached 60 ° C., 0.12 parts by weight of ferric sulfate 0.20 parts by weight of sodium pyrophosphate and 0.32 parts by weight of texturos were added to perform polymerization for 1 hour to prepare primary kraft radex.

18.75 parts by weight of styrene, 6.25 parts by weight of acrylonitrile, and 0.35 parts by weight of dodecyl mercaptan were mixed in the first graft radex and continuously added over 1 hour, followed by 30 minutes of cumene hydroperoxite 0.4 weight. Part was added to proceed with the second kraft reaction and the polymerization was terminated.

At this time, the polymerization time was 4 hours at 70 ℃.

Comparative Example 2

In the secondary kraft monomer addition method, 15 parts by weight of ion-exchanged water and 0.8 parts by weight of potassium oleate were prepared in the pre-emulsion state, and the same procedure as in Comparative Example 1 was conducted.

Comparative Example 3

0.4 parts by weight of cumenehydroperoxite added to the second kraft reaction was added in the pre-emulsion state, and the same procedure as in Comparative Example 2 was carried out.

The physical property results of Examples 1-4 and Comparative Examples 1-3 are shown in Table 1.

Claims (1)

1) Graft the SAN copolymer in the presence of butadiene-based rubber latex copolymer, styrene 0 in 100 parts by weight of the sum of the aromatic vinyl monomer and unsaturated nitrile monomer mixture and butadiene-based rubber latex used in the continuous dosing method through a multi-step reaction. -9.18 parts by weight of acrylonitrile, 0-3.07 parts by weight of a monomer mixture, emulsifier, molecular weight regulator, polymerization initiator and ion-exchanged water were added to the reactor in a part of the partition, and the reactor temperature was 40 ° C-65 ° C. At a first stage kraft by adding 0.001-0.35 parts by weight of a redox catalyst consisting of ferrous sulfate, sodium formaldehyde sulfoxylate, and ethylenediamine tetraacetic acid, and 2) freely distributing the residue to the primary kraft latex. 52.5-17.06 parts by weight of styrene and 17.5-5.69 parts by weight of acrylonitrile after being made into an emulsion state A two-stage reaction in which a monomer consisting of 1 hour to 4 hours is continuously added to make the graft polymerization uniform and increase the polymerization rate at a constant rate so that the polymerization rate is 90-95%, and 3) the two-step reaction. When the rate of polymerization reached 90-95%, a redox catalyst consisting of ferrous sulfate, sodium fordium aldehyde sulfoxylate, and ethylenediamine tetraacetic acid was added to 0.001-0.25 parts by weight to involve most of the unreacted monomers in the polymerization. A thermoplastic resin manufacturing method excellent in whiteness, characterized in that.