JPH0314856A - Core-shell polymer - Google Patents

Abstract

PURPOSE:To improve the impact strength, heat stability, and weathering properties of a polyoxymethylene resin by melt-blending the resin with a core-shell polymer which comprises a core of a rubber-like polymer and a shell of a glassy polymer and from which no anion is detected. CONSTITUTION:A core-shell polymer comprising a core consisting of a rubber- like polymer (having a glass transition temp. of 30 deg.C or lower) obtd. by polymerizing monomers contg. butadiene, butyl acrylate, etc., and a shell consisting of a glassy polymer (having a glass transition temp. of 60 deg.C or above) obtd. by graft copolymerizing methyl methacrylate, etc., onto the core polymer by emulsion polymn. in the presence of a nonionic surfactant and a neutral, radical- generating polymn. initiator [e.g. a dibasic acid salt of 2,2'-azobis(2- aminopropane) or hydrogene peroxide] is prepd. The core-shell polymer from which no anion is detected, comprises 50-90wt.% core and 10-50wt.% shell, and is useful for blending into a polyoxymethylene resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a core-shell polymer for polyoxymethylene resins, and to resin composites and resin moldings having excellent impact resistance obtained by melt-mixing this core-shell polymer.

Prior Art Polyoxymethylene (POM) resin is currently used as a material for various military articles (Gar-Reel, etc.).
Since the rIIgii attack resistance of the obtained hollow-shaped articles is not sufficient, many attempts have been made to improve this.

However, due to its structure, there is currently no other resin with sufficient compatibility with POM resin. Furthermore,
POM resins have poor thermal stability and are not suitable for blending at high temperatures.

In general, there are many proposals for core-shell polymers to be melt mixed into resins for the purpose of improving impact resistance. Among these, core-shell polymers, which have a rubber elastic body as a core and a glassy polymer as a shell, have a reproducible uniform dispersion because the state of dispersion in the resin is less affected by melt mixing conditions. It has the characteristic of being easily damaged.

Core-shell polymers are the w1 of many matrix resins including polycarbonate, polybutylene terephthalate, polyamide, polyphenylene oxide, and alloys of these polymers! It is used as a improving agent.

However, conventional core-shell polymers
It contained a fraction that promoted the thermal decomposition of O M PADo. For this reason, traditional core-shell polymers are
It was difficult to even blend it with M resin.

Moreover, even if blending was possible, the composition had poor thermal stability.

POM resin WfJg! i1! A composition with improved properties is disclosed, for example, in JP-A-59-155453. This is a thermoplastic IPN with polyurethane elastomer
However, in order to obtain sufficient impact resistance, it is necessary to add a considerable amount of polyurethane elastomer, which significantly reduces the elastic modulus and further increases the thermal resistance. There are many problems, including the inability to obtain sufficient financial stability and liquidity.

JP-A-59-136343 discloses a POM resin composition containing a rubber-like elastomer obtained by emulsion polymerization of C, -8 alkyl acrylate. However, special blending conditions are required to produce this composition, and a sufficiently stable POM resin composition cannot be obtained under normal blending conditions.

Furthermore, no efforts have been made to improve thermal stability during emulsion polymerization.

JP-A-63-33466 discloses a POM resin composition containing a core-shell polymer and a reactive titanate. However, even if this core-shell polymer is used, P
Decomposition of the OM resin composition occurs, and a stable resin composition cannot be obtained.

In particular, JP-A-59-36343 and JP-A-63-3
Regarding the core-shell polymer used in Example 3466, Comparative Example 1 shows that the thermal stability is poor.

JP-A No. 61-120849 discloses a P○M resin composition containing a rubber-like elastic body obtained by emulsion polymerization of butadiene, but this also does not involve any modification to the emulsion polymer. , poor thermal stability.

Special Publication No. 48-34830 contains P containing rubber-like elastic material.
Although OM resin composites have been disclosed, they also have poor thermal stability.

Further, JP-A-61-120849 discloses a POM resin composition containing a rubber-like elastic body obtained by emulsion polymerization of butadiene. However, the thermal stability of the resin composition cannot be said to be good.

Generally, polymer blends composed of crystalline polymers have a drawback that the strength and elongation of the weld portion are low. POM resin is a highly crystalline polymer. For example, a POM resin composition blended with a urethane elastomer to improve ILF impact properties will have extremely low weld strength and elongation.

Furthermore, POM resin is included in engineering plastics and cannot necessarily be said to have good weather resistance. especially,
ff9j ([Due to the s properties, the weather resistance of POM resin compositions blended with urethane elastomers is significantly reduced.

Problems to be Solved by the Invention As described above, in the prior art, POM1:i4 resin composition has sufficient impact resistance and also has excellent thermal stability. Development of improving agents is desired.

Furthermore, POM resin is particularly poor in weather resistance among similar engineering plastics. The above-mentioned conventional techniques have not particularly improved this point, and it is desired to develop a P○M resin composition that has improved impact resistance and weather resistance.

Means for Solving the Problems The present inventors conducted intensive research on core-shell polymers that provide POM resin compositions with excellent iIt impact properties, and found that the polymerization initiator and surfactant used during polymerization were POM resin compositions with excellent iIt impact properties.
It has been found that this has an adverse effect on the thermal stability of OM resin.

Furthermore, we conducted repeated studies to improve weld strength, elongation, and weather resistance.

Therefore, the inventors have discovered that the above-mentioned problems can be solved at once by melt-mixing core-shell polymers having the following structure, and have completed the present invention.

That is, the present invention provides a core-shell polymer having a core of a rubbery polymer and a shell of a glassy polymer, in which substantially no anions are detected, a method for producing the same, and a polyoxymethylene resin composition containing the core-shell polymer.
It is a resin molded article formed by molding the resin composition.

The anion content in the present invention is such that it cannot be detected by conventional anion qualitative tests.

For example, the measurement method is to weigh 5 g of a sample (core-shell polymer) into a 50 ml Erlenmeyer flask, add 20 ml of ion-exchanged water, and stir with a magnetic stirrer for 3 hours.

Next, No. The filtrate filtered through 5C filter paper was divided into two parts, and one half was added with 1% barium chloride aqueous solution with 0.0% barium chloride solution. 5 ml was added and the occurrence of turbidity was comparatively observed (qualitative test of sulfate ion)
.

Also, the same treatment was performed and 0.0% barium chloride was used instead of 1% barium chloride. An IN silver nitrate aqueous solution was added, and the occurrence of turbidity was comparatively observed (qualitative test for halogen ions).

Measurements for other anions such as metal salts of carboxylic acids are similarly carried out using measurement methods commonly used for qualitative tests.

Preferably, core-shell polymers are used in which these anions are completely absent.

The emulsion polymerization of the present invention can be carried out using, for example, the following surfactants and polymerization initiators.

As surfactants, ether type such as polyoxyethylene nonylphenyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, etc.
Widely used nonionic surfactants such as ester types such as polyoxyethylene monostearate, sorbitan ester types such as polyoxyethylene sorbitan monolaurate, and block copolymer types such as polyoxyethylene borioxypropylene block copolymers. Most of them are available. The type of addition thereof is appropriately selected depending on the particle stabilizing ability of the surfactant.

Since these surfactants are nonionic, they do not generate anions and are less likely to decompose the POM resin.

As a polymerization initiator, azobisisobutyronitrile, 2,
Azo polymerization initiators such as dimethyl 2'-azobisisobutyrate, 2,2''-azobis(2-aminobutyric acid) dihydrochloride, peroxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, hydrogen peroxide, etc. is used.

Since all of these polymerization initiators do not introduce anions to the ends of the core shell polymer, they are less likely to decompose the P○M resin.

For example, if emulsion polymerization is carried out in a reaction system that uses an anion-free surfactant and a non-persulfate polymerization initiator, the resulting core-shell polymer will be substantially anion-free. You can get something.

A POM resin composition using this core-shell polymer has excellent impact resistance.

The core-shell polymer in the present invention is obtained by a continuous multi-stage emulsion polymerization method in which a polymer of an earlier stage is then coated with a polymer of a later stage, a so-called seed emulsion polymerization method.

During particle generation polymerization, it is preferable to start the emulsion polymerization reaction by adding monomers, surfactants, and water to a reactor, and then adding a polymerization initiator.

The first stage of polymerization is a reaction that forms a rubbery polymer.

Examples of monomers constituting the rubbery polymer include conjugated dienes, alkyl acrylates in which the alkyl group has 2 to 8 carbon atoms, and mixtures thereof.

These monomers are polymerized to lower the glass transition temperature to -30°C.
The following rubbery polymers are formed.

Examples of such conjugated dienes include butadiene, isoprene, chloroprene, etc., but butadiene is particularly preferably used.

Examples of alkyl acrylates having 2 to 8 alkyl groups include ethyl acrylate, probyl acrylate,
butyl acrylate, cyclohexyl acrylate, 2
Examples include -ethylhexyl acrylate, but butyl acrylate is particularly preferably used.

In the first stage polymerization, monomers copolymerizable with conjugated dienes and alkyl acrylates, such as aromatic vinyls such as styrene, vinyltoluene, and α-methylstyrene,
Vinyl cyanides such as aromatic vinylidene, acrylonitrile and methacrylic nitrile, vinyl cyanide, alkyl methacrylates such as methyl methacrylate and butyl methacrylate, etc. can also be copolymerized.

If the first stage polymerization does not contain a conjugated diene, or even if it does contain a conjugated diene, 2 of the total monomer amount in the first stage is
When the amount is 0% by weight or less, high impact resistance can be achieved by using small amounts of crosslinking monomers and grafting monomers.

Examples of crosslinking monomers include aromatic divinyl monomers such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate, oligoethylene glycol diacrylate, and oligoethylene glycol diacrylate. Examples include alkane polyol polyacrylates or alkane polyol polymethacrylates such as methacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate, but in particular, butylene glycol diacrylate, Hexanediol diacrylate is preferably used.

Grafted things! Examples of - include unsaturated carboxylic acid allyl esters such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, and diallyl itacone-f, with allyl methacrylate being particularly preferably used.

Such crosslinking monomers and grafting monomers each account for 0.01 to 5% by weight of the total monomer amount in the first stage,
It is preferably used in a range of 0.1 to 2% by weight.

The rubbery polymer core preferably ranges from 50 to 90% by weight of the total core-shell polymer. When the weight of the core is less than or exceeds this range, the effect of improving the impact resistance of the resin composition obtained by melt-mixing the core-shell polymer may not be sufficient.

Furthermore, if the glass transition temperature of the core is higher than -30°C, the effect of improving low-temperature impact resistance may not be sufficient.

The outermost shell phase is formed of a glassy polymer.

Examples of monomers constituting the glassy polymer include methyl methacrylate and monomers copolymerizable with methyl methacrylate.

These monomers are methyl methacrylate alone or a mixture of methyl methacrylate and monomers copolymerizable with methyl methacrylate, and have a glass transition temperature of 60°C.
The above glassy polymer is formed.

As a monomer copolymerizable with methyl methacrylate,
For example, alkyl acrylates such as ethyl acrylate and butyl acrylate, alkyl methacrylates such as ethyl methacrylate and butyl methacrylate, styrene,
Examples include aromatic vinyl such as vinyltoluene and α-methylstyrene, aromatic vinylidene, vinyl cyanide such as acrylonitrile and methacrylonitrile, and vinyl polymerizable monomers such as vinylidene cyanide, but particularly preferred are ethyl acrylate, Styrene and acrylonitrile are used.

This outermost shell phase preferably ranges from 10 to 50% by weight of the entire core-shell polymer. When this outermost shell phase is less than this weight range or exceeds this weight range, the resin composition obtained by melt-mixing the raw core-shell polymer will be used! The effects of sex improvement may not be sufficient.

Furthermore, an intermediate phase may exist between the first stage and the final polymerization phase. For example, polymerized monomers having functional groups such as glycidyl methacrylate and unsaturated carboxylic acids, polymerized monomers that form glassy polymers such as methyl methacrylate, polymerized monomers that form rubbery polymers such as butyl acrylate, etc. The mesophase is formed by seeded emulsion polymerization.

Various types of such mesophases can be selected depending on the desired properties of the core-shell polymer.

Moreover, the polymerization ratio may be appropriately determined depending on the monomers used. For example, when a glassy polymer is used as the intermediate phase, the polymerization ratio thereof may be calculated as part of the shell, and in the case of a rubbery polymer, it may be calculated as part of the core.

The structure of core-shell polymers with such an intermediate phase is, for example, a multilayer structure in which there is another layer between the core and shell, or a structure in which the intermediate phase is dispersed in the core as fine particles. Examples include those with a salami structure. In a more extreme case with a core-shell polymer having a ξ structure, the intermediate phase to be dispersed may form a new core in the center of the core. A core-shell polymer having such a structure may be produced when a monomer represented by styrene is used as an intermediate phase ili monomer.

In addition, when a core-shell polymer with an intermediate phase is used, in addition to improving the W11 properties, it also improves the flexural modulus, increases the heat distortion temperature, and improves the appearance (suppression of surface peeling and pearlescent luster), and changes in color tone due to changes in the refractive index. ) will also be improved.

The core-shell polymer of the present invention can be taken out in the form of granules, flakes, or powder, for example, by the following method.

■Produce latex by a known seed emulsion polymerization method using the above-mentioned surfactant and polymerization initiator. (2) Next, the polymer is separated from the latex by freezing and thawing it.

■Next, centrifugal dehydration and drying.

By such a removal operation, much of the solvent, surfactant, etc. used during emulsion polymerization can be removed.

Alternatively, the latex can be dried and used as it is in step (2).

Furthermore, a spray drying method using a spray dryer is also one of the methods for removing the core-shell polymer from latex.

The core-shell polymer thus taken out may be further made into pellets using an extruder and a pelletizer, or it may be melt-mixed as it is with a resin as an impact modifier.

The POM resin composition according to the present invention contains 5 to 100 parts of the above-mentioned core shell polymer per 100 parts by weight of POM resin.
parts by weight, preferably 10 to 80 parts by weight, are melt-mixed.

If the amount of this core shell polymerer is less than 2 parts by weight, the effect of improving the mW impact properties of the resulting resin composite material may not be recognized, and if it is more than 100 parts by weight, the resulting resin composite material may have poor rigidity. , heat resistance may be significantly impaired.

POM resins used in the present invention include formaldehyde homopolymers and copolymers of formaldehyde or its cyclic oligomers and oxyalkylene groups having at least two adjacent carbon atoms in the main chain. Both polyoxymethylene homopolymer resins and polyoxymethylene copolymer resins can be used.

Melt mixing is employed to produce the POM resin composition according to the present invention. For melt mixing, an appropriate temperature range is usually selected in which the resin is melted and the viscosity is not extremely low between 180 and 240°C.

Melt mixing can be carried out using heated rolls, a Banbury mixer, or a single or multi-screw extruder. Furthermore, the resin composite according to the present invention may contain appropriate amounts of additives and other ingredients.

Examples of such additives include flame retardants, @type agents,
Examples include weatherability imparting agents, antioxidants, antistatic agents, heat resistance imparting agents, colorants, reinforcing agents, surfactants, inorganic fillers, lubricants, and the like.

Effects of the Invention The core-shell polymer according to the present invention exhibits excellent hardness W* properties when melt-mixed with POMI fat.

Furthermore, the resin composition using the core-shell polymer of the present invention has sufficient thermal stability compared to the resin composition using the conventional core-shell polymer shock modifier, and the resin composition using the urethane elastomer has sufficient thermal stability. It exhibits better fluidity, thermal stability, and appearance compared to

Furthermore, it is possible to provide a resin composition that is excellent in terms of weather resistance, weld elongation, and coherency.

EXAMPLES The present invention will be explained with reference to Examples and Comparative Examples below.
The present invention is not limited in any way by these Examples.

In addition, "r part" in Examples and Comparative Examples all represent parts by weight. Furthermore, the numerical values shown in Tables 1 and 2 are also expressed at the highest point.

Abbreviations used in Examples and Comparative Examples are as follows.

n-butyl acrylate BA ethyl acrylate EA methyl methacrylate
MMA vinyl acetate
VAc butadiene Bd styrene St glycidyl methacrylate GMA2-ethylhexyl acrylate} 2EHA hydroxyethyl methacrylate HEMA allyl methacrylate AI
MA1,4-futhylenecoulicol sea acrylate BGA deionized water
DIW polyoxyethylene nonylphenyl ether E950 (Kao (WJ) Emulgen 950) Polyoxyethylene nonylphenyl ether
E985 (Kao Corporation Emulgen 985) Polyoxyethylene lauryl ether
YX500 (Neugen YX-500 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Polyoxyethylene monostearate S40 (NOF (vi) Nonion S-40) Polyoxyethylene monostearate! Laure}
LT221 (Nonion LT-221 manufactured by NOF Corporation)
Soybean octyl sulfosuccinate
NP (Daiichi Kogyo Seiyaku Co., Ltd. Neocol P) Sodium hydrogen carbonate SBC2,2'-
Aso Heath (Methyl Isobutylate)
v6 0 1 (manufactured by Wako Pure Chemical Industries, Ltd. V601) 2,2'-Asoheath (2-aminopropylene) di@acid temperature V50 (manufactured by Wako Pure Chemical Industries, Ltd. V50) Hydrogen peroxide H202 Vitamin C VC Sodium persulfate SPS [ Example 11 Preparation of Core-Shell Polymer A
1125g of W and 135g of a 10% aqueous solution of E950 were charged, and the temperature was raised to 70°C while stirring under a nitrogen stream. 90 g of the first stage monomer mixture consisting of fl. E
A mixed solution consisting of 45 g of a 10% aqueous solution of 950 and 90 g of DIW was sufficiently emulsified with a disper, and then added.
After 10 minutes of dispersion, 3.6 g of V601 was added to polymerize the seed particles.

First stage monomer BA 1792.8g AIMA 3.6g BGA 3.6g Then the remaining 1710g of first stage monomer mixture}: E9
50(7) 10% aqueous solution 1500g. A monomer emulsion containing 525 g of DIW was continuously fed over 250 minutes to carry out seed polymerization.

After raising the temperature to 90°C and observing the working time, the mixture was cooled to 70°C and the second stage of polymerization started.

1.5 g of V601 was added, and 1125 g of the second stage monomer emulsion of the next set was continuously fed over 200 minutes to carry out seed polymerization.

Second stage monomer emulsion MMA 405.0gEA
45. OgNPEb 10
% aqueous solution 362.0gDIW
313.0g was heated to 90°C, aged for 1 hour, cooled, and filtered through a 300-mesh stainless wire mesh to obtain a core-shell polymer latex.

This latex was frozen at -15°C, filtered through a glass filter, and then dried with air at 60°C overnight to obtain core-shell polymer A.

16i Example 2] Production of core-shell polymer B 1320 g of DIW and 10% aqueous solution sag of E950 were charged into a 5-liter polymerization vessel equipped with a reflux condenser, and the temperature was raised to 70° C. while stirring under a nitrogen stream. After adding 77 g of a first stage monomer mixture consisting of the following set and dispersing for 10 minutes, 154 g of a 2% aqueous solution of V50 was added to polymerize the seed particles.

First stage monomer BA 1533.84gA
IMA 3.08gBG
3.08g of A, then 10% of E950 to the remaining 1463g of the first stage monomer mixture.
A monomer emulsion prepared by adding and mixing 440 g of % aqueous solution and 440 g of DIW was continuously fed over 180 minutes to carry out seed polymerization.

After aging at 70°C for 1 hour, the second stage of polymerization was carried out.

66 g of a 2% aqueous solution of V50 was added, and 1120 g of a second-stage monomer emulsion of the next set was continuously fed over 60 minutes to carry out seed polymerization.

Second stage monomer emulsion MMA 594.0gEA
66. ogE950 10% aqueous solution 220.0gDIW 4
40.0g was heated to 80°C, aged for 1 hour, cooled, and filtered through a 300-mesh stainless wire mesh to obtain core-shell polymer latex.

This latex was frozen at -15°C, filtered through a glass filter, and then dried with air at 60°C overnight to obtain core-shell polymer B.

[Example 3] Production of core-shell polymer 10 In a 2-liter polymerization vessel equipped with a reflux condenser, 600 g of DIW and 500 g of YX (
7) 20 g of a 10% aqueous solution was charged, and the temperature was raised to 35° C. while stirring under a nitrogen stream. VAc35g. EA engineering 5g
After adding 50 g of a monomer mixture consisting of and dispersing for 10 minutes, 12 g of a 3% aqueous H20 solution and VC
Seed particles were polymerized by adding 12 g of a 2% aqueous solution.

First stage monomer (665 g out of 700 g below)
BA 697.20gAIMA
1.40gBOA
1.40g followed by 665g of first stage monomer
35g of 10% aqueous solution of YX500. A monomer emulsion mixed with 95 g of DIW was continuously fed over 240 minutes, and 72.5 g of a 3% aqueous solution of H20 and V
Seed polymerization was carried out by continuously feeding 72.5 g of a 2% C aqueous solution over 300 minutes. The monomer emulsion feed was cooled to maintain the temperature between 35°C and 40°C.
At that temperature, after finishing the feed, the mixture was aged for a working time and then entered into the second stage of polymerization.

32.9 g of a 3% H20 aqueous solution and 32.9 g of VC were continuously fed over 150 minutes, and 431 g of a second-stage monomer emulsion having the following composition was continuously fed over 90 minutes to perform seed polymerization. Note that during feeding of the monomer emulsion, the temperature was maintained at 35°C to 40°C.

Second stage monomer emulsion MMA 253.8gEA
28.2gYX500 10%
Aqueous solution 47.0gDIW 1
After feeding at that temperature, the mixture was aged for 1 hour, cooled, and filtered through a 300-mesh stainless wire mesh to obtain a core-shell polymer latex.

This latex was frozen at -15°C, passed through a glass filter, and then dried with air at 60°C all day and night to obtain core-shell polymer C.

[Example 4] Production of core-shell polymer D In a 5 liter autoclave, 10 g of DIWI, 000 g of E950 was added.
% aqueous solution was charged, and the temperature was raised to 70°C while stirring under a nitrogen stream.

After adding 5 Lg of the first stage monomer mixture consisting of the following groups and dispersing for 10 minutes, add 1 liter of a 2% aqueous solution of V50.
35 g was added to polymerize the seed particles. First stage monomer (feed 1,064g out of the 1,120g below) B
d 784g St 336g Subsequently, 1,064g of first stage monomer and E950
Seed polymerization was performed by continuously feeding a mixed solution of 178 g of a 10% aqueous solution of and 680 g of DIW over 420 minutes.

After finishing the feeding, add 33g of 2% aqueous solution of V50,
The temperature was raised to 80°C and ripened for one hour.

700 g of DIW was slowly added, and the mixture was cooled to 70° C. to begin the second stage of polymerization.

72 g of a 2% aqueous solution of V50 was added, and 480 g of a second-stage monomer mixture having the following composition was continuously fed over 90 minutes to carry out seed polymerization.

Second stage monomer MMA 333.6g St 144. Og BGA 2.4g DIW 102.0g After the feeding was completed, the temperature was raised to 80°C and aged for one hour. After cooling, the mixture was filtered through a 300-mesh stainless wire mesh to obtain a core-shell polymer latex.

This latex was frozen at -15°C, filtered through a glass filter, and dried with air at 60°C overnight to obtain core-shell polymer D.

[Examples 5 to 101 Production of core-shell polymer E-J Core-shell polymer E-J was produced in the same manner as in Example 2 using the monomer set shown in Table 1 below.

[Example 11] Production area of POM resin composite (1) 90 parts of POM copolymer resin Tenac C3510 manufactured by Kaaru Kogyo Co., Ltd. and 1 part of core shell polymer A manufactured in Example 1
After drying until the moisture content is 0.03% or less, POM is melt-mixed using a twin-screw extruder PCM-30 manufactured by Ikegai Tekko Co., Ltd. at a cylinder temperature of 200°C and a Gui head temperature of 200°C. Pellets of resin composition (1) were obtained.

[Examples 12 to 24] POM resin composites (2) to (l
POM resin compositions (2) to (14) shown in Table 2 were produced in the same manner as in Production Example 11 of 4).

[Example 25] POM homopolymer resin Tenac 30 manufactured by Asahi Kasei Kogyo Co., Ltd.
Using 8Q parts of Polymer No. 10 and 20 parts of the core-shell polymer A produced in Example 1, a POM resin composition (15) having the structure shown in Table 2 was manufactured in the same manner as in Example 1l.

[Comparative Example 1] Production of POM resin composition (Part 6) W impact improver L (manufactured by Rohm & Haas (manufactured by Rohm & Haas) KM330) and POM
P○M resin composite (technique 6) using copolymer resin
was manufactured and its pereft was obtained.

[Comparative Example 2] Production of POM resin composition (Process 7) Impact modifier M (Takeda Birdy Urethane (i) T-aao
) and POM:l polymer resin to produce a POM resin composition (17) and obtain pellets thereof.

[Comparative Example 3] Production of core-shell polymer N and POM resin composition (18) 125 g of DIW was placed in a 5 liter polymerization vessel equipped with a reflux condenser.
, 50 g of NPI% aqueous solution, and LOOg of SBCI% aqueous solution were charged, and the temperature was raised to 70° C. with stirring under a nitrogen stream.

After adding 100 g of a first-stage monomer mixture consisting of the following composition and dispersing it for 10 minutes, 200 g of a 32% SP aqueous solution was added to polymerize seed particles.

First stage monomer BA 1992g AIMA 4.0g BGA 4. Next, add NPI to the remaining 1900g of the first stage monomer mixture.
A monomer emulsion prepared by adding and mixing 1125 g of SBCI% aqueous solution and 100 g of SBCI% aqueous solution was continuously fed over 120 minutes to perform seed emulsion polymerization.

After raising the temperature to 90'C and aging for 1 hour, the mixture was cooled to 70'C and the second stage of polymerization was carried out.

50 g of SP82% aqueous solution was added, and 775 g of a second-stage monomer emulsion having the following composition was continuously fed over 45 minutes.
Seed emulsion polymerization was performed.

Second stage monomer emulsion MMA 450.0g EA 50.0g NP 225.0g SBCI% aqueous solution 50.0g The temperature was raised to 90°C and matured for 1 hour, then cooled and filtered through a 300 mesh stainless wire mesh. A core shell polymer latex was obtained.

This latex was frozen at -15°C, passed through a glass filter, and then dried with air at 60°C overnight to obtain core-shell polymer N.

A POM resin composition (18) was produced using the obtained core-shell polymer N and POM copolymer resin, and pellets thereof were obtained.

[Comparative Example 4] Production of Core-Shell Polymer K Core-shell Polymer K was produced in the same manner as in Example 2 using the monomer set shown in Table 1 below.

[Comparative Example 5] Production of POM resin composition (19) A POM resin composition (19) having the composition shown in Table 2 was produced in the same manner as in Example 1l.

The obtained pellets were colored yellow, and the thermal stability of the composition itself was also quite poor.

[W impact resistance test of resin molded products] After drying the resin assemblies (1) to (l9) at 120°C for 4 hours, the cylinder temperature was adjusted using an injection molding machine TS-10O manufactured by Nichisei Jushi Co., Ltd. Shaping was performed at a nozzle temperature of 200°C.

Izod street impact test specimens with a thickness of 3.2 mm and a thickness of 6.4 mm specified in JIS K7110 were prepared by cutting a notch. With these test pieces, 23°C Niokel W! ! ! ! The values were measured in accordance with JIS K7110G. As a result, POM resin compositions (6) and (18)
(Comparative Examples 1 and 3) cannot be blended, and
POM resin composition (17) (Comparative Example 2) had problems with weld elongation retention, weather resistance, thermal stability, and fluidity.

The blending results are shown in Table 2.

[Measurement of weld elongation retention rate of resin molded products] JIS K
In the tensile test piece specified in JIS K7113, the ratio of the tensile elongation at break between the two-point test piece with gates at both ends and the one-point gate at one end was measured using a tensile test method based on JIS K7113.

The results are shown in Table 2.

[Weather resistance test of resin molded articles] The injection molded flat plate was exposed for 100 hours using a Sunshine Weather Meter manufactured by Suga Test Instruments, and the color difference (ΔE
) was measured using an E80 color measuring machine manufactured by Nippon Denshoku Industries.

The results are shown in Table 2.

[Qualitative test of anion] Core-shell polymer A- obtained in Examples and Reference Examples
Regarding K, anions contained in them were detected.

■Sample (core-shell polymer or impact modifier) 5
g into a 50 ml Erlenmeyer flask, add 20 ml of ion-exchanged water, and stir with a magnetic stirrer for 3 hours.

Next, No. 5C: Divide the filtrate through filter paper into two parts.
0.5 ml of a 1% barium chloride aqueous solution was added to one side, and the occurrence of turbidity was comparatively observed (qualitative test for sulfate ions).

In this qualitative test, no anions were detected in core-shell polymers A to J.

Anions were detected from core-shell polymers L and N.

■Sample (core-shell polymer or impact modifier) 5
g into a 50 ml Erlenmeyer flask, add 20 ml of ion-exchanged water, and stir with a magnetic stirrer for 3 hours.

Next, No. The filtrate filtered through 5G filter paper was divided into two parts, and one part was treated with 0.0% barium chloride instead of 1% barium chloride. An IN silver nitrate aqueous solution was added, and the occurrence of turbidity was comparatively observed (qualitative test for halogen ions).

In this qualitative test, no anions were detected in core-shell polymers A to J. ■Core shell polymer K
It has been found that the surfactant used is contained in the core-shell polymer, and it is clear that a carboxylic acid anion is present in this core-shell polymer.

Claims (1)

Claims: 1) A core-shell polymer with substantially no detectable anions, having a core of a rubbery polymer and a shell of a glassy polymer. 2) The method for producing a core-shell polymer according to claim 1), characterized in that the emulsion polymerization is carried out using a nonionic surfactant and a polymerization initiator whose generated radicals are neutral. 3) A polyoxymethylene resin composition comprising the core-shell polymer according to claim 1). 4) A polyoxymethylene resin molded product obtained by molding the resin composition according to claim 3).