JPS59166546A - Resin composition for powder forming - Google Patents

Abstract

PURPOSE:The titled composition that is obtained by coating a vinyl chloride resin absorbing a specific amount of plasticizer with a thermoplastic polymer emulsion containing vinyl chloride polymer emulsion of specific particle sizes at a specific coating ratio, thus showing high powder flowability and good flatting properties. CONSTITUTION:The objective composition is obtained by coating (A) a product which is prepared by allowing (i) a vinyl chloride resin, preferably containing vinyl chloride polymer emulsion of 0.05-1mu averge particle size, a methyl methacrylate polymer emulsion or a styrene-acrylonitrile polymer emulsion containing 20-40wt% of acrylonitrile, to absorb (ii) X of a plasticizer, according to the equation where X is the amount of the plasticizer in pts.wt. per 100pts.wt. of the vinyl chloride resin, Y is the viscosity-average polymerization degree of the vinyl chloride resin, with (B) a thermoplastic polymer emulsion in an amount more than 5wt%. EFFECT:It shows high melt flowability and surface smoothness on molding and coating.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to the production of powder molded bodies that do not undergo thermal deterioration, have excellent powder fluidity and meltability during molding or painting, and have excellent surface smoothness or matte properties. The present invention relates to a resin composition for powder molding that enables the following.

Recently, various molding methods and coating methods using finely powdered synthetic resins have been developed, and typical examples include rotational molding, powder coating, fluidized dip coating, and electrostatic coating. For example, the rotational molding method is a method in which a synthetic resin is sintered along the inner surface of a desired mold to create a one-piece composite, and the fluidized dip coating method is a method in which synthetic resin is sintered along the inner surface of a desired mold. to melt the attached surface resin powder,
This is a method of forming a resin film.

The synthetic resins used in these molding and painting methods are required to have excellent powder flow characteristics, melting properties, and stability that does not cause thermal deterioration during heating, as well as to ensure the smoothness and gloss of the surface of the resulting molded product. Recently, the number of cases requiring erasability has been increasing.

The purpose of this product is to give it a luxurious feel that does not resemble plastic when used in i4 automobile interior materials, etc., and it has become an important element in the recent interior materials market that is oriented toward luxury products.

In the present invention, the surface smoothness of a molded article refers to a state in which there are no irregularities such as pockmarks that occur on the side that does not come into contact with a mold, etc., and matteness refers to a state in which there are no microscopic irregularities on the entire surface. can be,
When viewed as a whole, it is smooth and lacks luster.

The present inventors have previously developed a vinyl chloride resin composition containing a plasticizer as a vinyl chloride resin composition for powder book molding that has excellent powder fluidity and melting properties and does not undergo thermal deterioration during processing. and a powdered vinyl chloride resin composition containing a plasticizer and having a particle size of less than S μ without heating was proposed as Japanese Patent Application No. 14'. The surface smoothness of the side not in contact with the mold of the invention is not sufficient,
Only a shattered and extremely glossy molded product can be obtained. If this composition is subjected to powder molding and molded at a low temperature in an attempt to forcibly remove the luster, a certain degree of matteness can be achieved, but the physical properties such as mechanical strength of the molded product deteriorate, making it very difficult to use for practical use. do not have.

The present inventors have conducted intensive studies to produce a matte-like powder molded product without deterioration of physical properties such as mechanical strength of the molded product. 90% with specific thermoplastic emulsion polymers
It has been discovered that by applying the edges, a matte molded body can be obtained without deteriorating the powder fluidity, melting properties, or mechanical properties of the molded body. The present invention was achieved by discovering that a molded product with excellent powder flowability, melting properties, and surface smoothness can be obtained even when the '0+J1 coverage rate is less than 9'θ%.

That is, the purpose of the present invention is to improve powder fluidity during powder molding,
It is an object of the present invention to provide a resin composition for powder molding, which has excellent melting properties and thermal stability, and can produce a molded article with a smooth or matte surface without reducing mechanical strength.

Therefore, the gist of the present invention is a resin composition for powder molding, which is formed by coating a thermoplastic emulsion polymer on a vinyl chloride resin that has absorbed a plasticizer, wherein the plasticizer is a vinyl chloride resin that has absorbed a plasticizer. Using the amount of X expressed in the range of the following general formula between the viscosity average degree of polymerization Y of It is the part by weight of the plasticizer per 700 parts by weight of the resin, and the value is 10 or more, and Y represents the viscosity average degree of polymerization of the vinyl chloride resin. ] The thermoplastic emulsion polymer has an average particle diameter of θ, 07~/
μm of vinyl chloride emulsion 1 coalescence, methyl methacrylate emulsion polymer or styrene-acrylonitrile emulsion copolymer (acrylonitrile content - 〇~1I)
oxx-qb), and the resin composition for powder molding is characterized in that the surface area of the vinyl chloride resin that has absorbed a plasticizer is covered by the thermoplastic emulsion polymer at least 3%. It exists in things.

To explain the present invention in detail, a vinyl chloride resin that has absorbed a plasticizer, which is one of the components of the composition of the present invention, is melted, for example, the vinyl chloride resin and the plasticizer are mixed at a temperature below the melting temperature of the vinyl chloride resin. Specifically, it is a powdered vinyl chloride resin obtained by heating and mixing at a temperature of 130° C. or lower, absorbing a plasticizer into the vinyl chloride resin, and then cooling the resin. The vinyl chloride resin is a homopolymer of vinyl chloride or a copolymer of vinyl chloride and a monomer that can be copolymerized with it, and the particle size is made large and porous to improve the absorption of plasticizers. In order to achieve this, it is usually produced by a suspension polymerization method or a bulk polymerization method, and among these, it is preferably produced by a suspension polymerization method.

Examples of monomers that can be copolymerized with vinyl chloride include vinyl carboxylic acids such as ethylene, propylene, butene, pentene, butadiene, styrene, α-methylstyrene, acetic acid, caproic acid, caprylic acid, and benzoic acid. Esters or aryl esters, number of carbon atoms in alkyl group /~/: i (0+''ll) dialkyl maleic acid or 7-malic acid esters, acrylonitrile, vinylidene chloride, vinylidene cyanide, alkyl group CI~, 6 Alkyl vinyl ethers, N-vinylpyrrolidone, vinylpyridine, and nylsilanes, alkyl groups ○, acrylic acid alkyl esters of ~1. Copolymerization can be carried out within the range of `Ioxx parts or less, preferably 30 parts, relative to fJ' parts.

Whether a vinyl chloride resin having a certain degree of polymerization should be selected depends on the type and amount of the plasticizer used.

A favorable relationship between the concentration of vinyl chloride resin and the amount of plasticizer used is expressed by the following general formula.

ri00 (/+ millet) ≧ Y ≧ 250 (/ ten rows) [in the formula,
X is the amount of plasticizer used per part of vinyl chloride resin/θOX, which is a value greater than or equal to t'), and Y represents the average viscosity of the vinyl chloride resin. 7- The amount of plasticizer used is limited by the degree of vinyl chloride resin used when the amount of plasticizer used is greater than the above-mentioned amount in the desired plasticizer, amount, and formulation. This is because the fluidity of the powder deteriorates markedly and the plasticizer bleeds from the molded body so much that it cannot be put to practical use.

On the other hand, if an amount smaller than the specified amount is used, the physical properties will be inferior due to processing temperature constraints. The amount of plasticizer used is generally such that the degree of polymerization and plasticizer are within the above-mentioned relationship range, and 10014 parts of vinyl chloride resin and 30 parts of plasticizer are used. It is most preferable that the amount is 1 part ON.

The plasticizer that can be absorbed into the vinyl chloride resin is not particularly limited as long as it is used for the vinyl chloride resin, but dialkyl phthalates, dialkyl adipates, and trialkyl having an alkyl group having 0 to 3 carbon atoms can be used. trimellitates, dialkyl sepacates, dialkyl azelates, alkyl benzyl phthalates, trialkyl phosphates, alkylaryl phosphates, polyester plasticizers, etc. 8- Specific examples include di-n-butyl phthalate, phthalate, etc. Di-n-octyl acid, dicoethylhexyl phthalate (DOP), diisooctyl phthalate, octyldecyl phthalate, diisodecyl phthalate, butylbenzyl phthalate, dicoethylhexyl isophthalate, dicoethylhexyl adipate (DOA), adipine acid di-
n-decyl, diisodecyl adipate, trimeri*) acid-) lycoethylhexyl azelaate, diptyl sebacate, dicoethylhexyl sebacate, tributyl phosphate, tricoethylhexyl phosphate, coethylhexyl phosphate Examples include diphenyl, tricresyl phosphate, etc., and one or a mixture of two or more of these may be used.

In addition, other additives such as stabilizers, colorants, fillers, secondary plasticizers, etc. may be added to the vinyl chloride resin that has absorbed the above-mentioned plasticizer to the extent that they do not adversely affect powder molding. may have been done.

Thermoplastic emulsion polymers used to coat the surface of vinyl chloride resins that have absorbed plasticizers include vinyl chloride emulsion polymers, methyl methacrylate emulsion polymers, and styrene-acrylonitrile emulsion copolymers (acrylonitrile content: -0-1IO, preferably 25 to 35].

This emulsion polymer has a primary average particle size of o, o! r~1μ
It is good to be in the range of m, preferably 0.0 left to o, g
[mu]m5 Particularly preferably in the range o, or~θ, 3 μm.

If the particle size is smaller than O or OS μm, the fluidity is not good. On the other hand, if the particle size is larger than 1 μm, a molded product with good surface smoothness cannot be obtained, and the physical properties of the molded product will be poor.

These emulsion polymers are made by emulsifying the main monomer of the emulsion polymer with a monomer copolymerizable with it, within a range that does not adversely affect the production of the resin composition for powder molding or the powder molding process. It may be a copolymer, and other additives such as stabilizers, colorants, fillers or plasticizers may be added.

These emulsion polymers are composed of a mixture of vinyl chloride monomer, methyl methacrylate monomer, and styrene to acrylonitrile monomer. Conventional emulsion polymerization methods in which a monomer mixture is reacted with deionized water, an emulsifier, and a water-soluble polymerization initiator, or a single monomer or a monomer mixture described above is reacted with deionized water, an emulsifier, and an oil-soluble After emulsification treatment with a polymerization initiator, a latex obtained by reaction is produced by a conventional drying method such as spray drying or salting out coagulation followed by dehydration drying. The amount of the copolymerizable monomer to be used is preferably as small as possible, and is generally preferably less than 04 of the total monomers.

These emulsion polymers are drawn onto the surface of the vinyl chloride resin that has absorbed the plasticizer and are emulsified with the vinyl chloride resin that has absorbed the plasticizer using a Hahenschel mixer, ribbon blender, crusher, etc. This is very easily accomplished by simply mixing the polymers.

The coverage rate varies depending on the type of vinyl chloride resin used to absorb the plasticizer, the type and amount of the emulsion polymer, the type of mixer, the mixing time, etc., but it can be easily determined by conducting some preliminary experiments. can do.

For example, it has excellent powder flow characteristics, melting characteristics, and thermal stability.
In addition, for the purpose of obtaining a powder molded product with excellent surface smoothness, the coverage ratio of the vinyl chloride resin that has absorbed the plasticizer with the thermoplastic emulsion polymer is &1 or more and less than 90%,
Preferably, it is in the range of g-go%, and in order to achieve this coverage, the mixing ratio of the vinyl chloride resin that has absorbed the plasticizer and the thermoplastic emulsion polymer is generally adjusted to the former/latter ratio. By weight ratio? It is desirable that the range is 9//-407'IO. In addition, for the purpose of producing a powder compact having excellent powder flow properties, melting properties, and thermal stability and having a matte surface, it is preferable that the coverage is 90% or more; Generally, the mixing ratio of the thermoplastic emulsion polymer of the vinyl chloride resin that has absorbed the plasticizer is the former/the latter in a weight ratio of 9/A; ~5s71
A range of Is is sufficient, and even if an emulsion polymer exceeding this range is used, the matting effect will not be improved more than necessary, resulting in an economic disadvantage. When the coverage rate is smaller than qoqb, it becomes difficult to exhibit the matting effect.

The powder molding resin composition of the present invention itself has excellent powder flow characteristics, and since it melts at a relatively low temperature, it can be easily molded and has excellent thermal stability.

Furthermore, when the composition of the present invention is subjected to various powder molding methods, depending on the difference in coverage with the emulsion polymer, a molded product with a smooth surface on the side not in contact with a mold or the like may be obtained, or a molded product with a glossy surface may be obtained. There is a difference in whether a molded product with an erased surface can be obtained, and a wide variety of powder molded products can be produced.

Therefore, the composition of the present invention can be applied to various molding methods such as rotational molding, powder coating, fluidized dip coating, electrostatic coating, etc.
It can be effectively used as a coating method, and its industrial value is extremely high.

The composition of the present invention will be described in detail below using raw material production examples and examples, but the present invention is not limited to the following examples unless it departs from the gist thereof.

Raw material production example/Production method of thermoplastic emulsion polymers [I] to [Vl] Add 2 2 liters of deionized water to a 31-volume stainless steel autoclave.
After adding 00 parts by weight, sodium lauryl sulfate (parts by weight shown in the table), potassium persulfate o, and tr parts by weight, and purging the inside of the autoclave with nitrogen, 10 parts by weight of vinyl chloride monomer
0 parts by weight was added and reacted at kg°C for 3 hours.

After removing unreacted residual monomers, the resulting latex was freeze-dried to obtain a vinyl chloride emulsion polymer having the primary average particle diameter shown in Table/.

Table l Raw material production example - Production method of thermoplastic emulsion polymer CVI'J 3 In a 1-volume stainless steel autoclave, deionized water - XX parts by weight, sodium lauryl sulfate / part by weight, potassium persulfate 0.3 parts by weight, Methyl methacrylate 100! After replacing the gas phase with nitrogen, the temperature was raised to 70°C, and the temperature was raised to 70°C.
I let it react over time. After removing unreacted residual monomers, the obtained latex was spray dried to obtain a methyl methacrylate emulsion polymer [VI]. -th average particle size was 0.1 μm.

15- Raw material production example 3 Production method of thermoplastic emulsion polymers [■] to [X] 3 Into a stainless steel autocup 1/- cup, add a monomer mixture of styrene and acrylonitrile in the proportions shown in Table 1. Then, out of 100 parts by weight of the total monomer mixture, 20 parts by weight, deionized water, 20 parts by weight, sodium lauryl sulfate/part by weight, and potassium persulfate O,S were added, and the gas phase was replaced with nitrogen. Thereafter, the temperature was raised to goC to start the reaction. During the reaction, go parts by weight of the remaining monomer mixture were successively added over one hour, and after the addition was completed, the reaction was allowed to proceed for three hours to produce a latex of a styrene-acrylonitrile emulsion copolymer. The latex was spray-dried to obtain an emulsion polymer having an acrylonitrile content and an average primary particle size as shown in the table.

16 - Table - The -order average particle diameter was measured by electron microscopy observation.

Examples 1 to 3, Comparative Example 1 - 700 parts by weight of vinyl chloride straight polymer (suspension polymerized product) with viscosity average degree of polymerization/goo, mercaptotin stabilizer/parts by weight, phthalate-gecoethylhexyl go
Parts by weight were put into a Henschel mixer, heated while stirring and mixing, and stirring was continued until the resin temperature rose to 130°C to absorb the plasticizer into the vinyl chloride straight polymer. Cool the polymer while stirring, and when the resin temperature of the polymer reaches AO°C, add the emulsion polymer shown in Table 3 to the polymer at a predetermined ratio, and continue mixing for the time shown in Table 3. did.

In the composition thus prepared, the surface of the vinyl chloride resin that has absorbed the plasticizer is coated with the emulsion polymer at the coverage ratio shown in Table 3.

Table 3 shows the evaluation results when these resin compositions were subjected to powder molding. When using emulsion polymer, methyl methacrylate emulsion polymer, styrene-acrylonitrile emulsion copolymer,
It can be seen that for the first time, a powder compact with good physical properties and a good matte state can be obtained.

In addition, the characteristics of the resin composition for powder molding and the physical properties of the molded article in the examples were measured as follows.

(1) Measurement of coverage rate This was done by observing electron micrographs.

In order to calculate the coverage rate, it is necessary to calculate the surface area of the particle and the 170 area of the covered part.

When a spherical particle is photographed, it is difficult to fairly evaluate the surface area of the tilted part, so it is expressed as the ratio of 1ρ to the part that can be considered to be approximately horizontal.

For example, in the case of a photograph of a spherical particle, assuming that the diameter of the particle on the plane is R, the coverage of a portion surrounded by a diameter of //3R from the center was determined. According to this method, a very accurate damage ratio can be obtained.

(2) Powder fluidity: Pour 00 ml of the composition into the water barrel for the bulk density measuring device of J.K.S.K. I judged sadness.

(3) Stretch Powder The molding composition was coated on aluminum foil to a thickness of 1/2 mm, and sintered for 70 minutes in an oven controlled at 200°C. It was measured.

19- (4) Matte state The film obtained in item (3) was visually evaluated on a five-point scale. Grade 3 (good matte) - Grade 7 (poor).

Table 3 20 Example g1 Comparative Example j--A Vinyl chloride resins shown in Table G (both suspended-MM compound,
100 parts by weight of straight polymer), part of diisodecyl phthalate/-xox*, and 7M parts of tin-based stabilizer at 110°C
The mixture was heated and mixed for 1 hour using a ribbon blender whose temperature was adjusted to absorb the plasticizer. g of cyclized vinyl resin and emulsion polymer [v1]! ;//S (weight ratio) and cross-mixed for 20 minutes in a crusher, a vinyl chloride resin composition for powder molding having a covering rate by the emulsion polymer shown in Table D was obtained. It was done. A powder compact was produced from the composition in the same manner as in Example 1. The powder characteristics of the composition and the evaluation results of the molded body are also listed in the table.
7-57. )≧Y≧ko r'.

It can be seen that excellent results were obtained when a vinyl chloride/θO 2 resin having a degree of unity within the range of (/+1) was used.

Table G Examples 9 to 7, Comparative Examples 7 to 10 Powder molding resin compositions with different coverage rates were produced in the same manner as in Example 1, and the characteristics of the compositions and the surface of powder molded bodies were The smoothness was measured and recorded in Table 5.

The meltability, surface smoothness, and thermal stability were measured by the following methods.

(4) A resin composition for powder molding was coated on meltable aluminum foil to a thickness of /m7A, heated to 7g at 0°C, and judged based on the time it took to become a transparent film.

(5) Coating the resin composition for powder molding to a thickness of 2 mjl on a smooth surface aluminum foil, sintering it for 3 minutes in an open air temperature controlled at 200°C, and using the obtained sheet as a small plate type all-purpose surface. The degree of unevenness was examined using a measuring machine. It is expressed as the difference between the maximum thickness of the convex portion and the minimum thickness of the concave portion.

(6) Thermal Stability The transparent film produced in Section (4) was heated at 220° C. in an open gear, and evaluated based on the time it took for the film to change color.

23- Table 3 24-Example/g, Comparative Example 1/~/:l Example g and Comparative Example j, Powder with a coverage of less than 90% was prepared using the vinyl chloride resin used in A in the same manner as in Example g. A resin composition for body molding was produced, and the powder fluidity, meltability, thermal stability, and surface smoothness of the molded body were measured and shown in Table 6.

The results show that the surface smoothness is poor when a vinyl chloride resin having a degree of polymerization outside the range of 00(/+π1≧Y≧Kota0(/11π1) is used.

Table 6 Example 1 - Co/By the same method as in Example 1, the surface of the vinyl chloride resin that had been made to absorb a plasticizer was coated with the thermoplastic emulsion polymer shown in Table 7.

The coating was applied to achieve a coverage rate of Table 7 also lists the powder properties and molded body evaluation results of these compositions.

Table 7 Patent applicant Mitsubishi Monsanto Kasei Co., Ltd. Representative
Person Patent attorney Hase - 7 others 127= =396-

Claims (1)

[Scope of Claims] (1) A powder molding resin composition comprising a vinyl chloride resin that has absorbed a plasticizer and is coated with a thermoplastic emulsion polymer, wherein the plasticizer is a vinyl chloride resin that has absorbed a plasticizer. xJ expressed in the range of the following general formula between the viscosity average degree of polymerization Y and
using tt, X X7
00 (/ Jucho)≧Y≧ko! ; 0 (/ 10-7;
) [wherein, X is M parts of the plasticizer per 100 parts by weight of the vinyl chloride resin, and Y represents the viscosity average degree of polymerization of the vinyl chloride resin. ] The thermoplastic emulsion polymer has an average particle diameter of θ, θS-1
using at least one of a vinyl chloride emulsion polymer, a methyl methacrylate emulsion polymer, or a styrene-acrylonitrile emulsion copolymer (with an acrylonitrile content in the range of 20 to 50 g), and a plasticizer. A resin composition for powder molding, characterized in that the coverage of the surface area of the vinyl chloride resin absorbed by the thermoplastic emulsion polymer is at least &%. The resin composition for powder molding according to claim 17, which enables the production of a powder molded body with a smooth surface. The resin composition for powder book molding according to claim 17, which enables the powder book molding.