JPH0465102B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Object of the Invention The present invention relates to a vinyl chloride resin plastisol composition that provides a vinyl chloride resin product with improved water absorption and whitening properties and thermal stability. (Industrial Application Field) The vinyl chloride resin plastisol composition of the present invention can be used to produce transparent vinyl chloride resin products, especially transparent products that have good thermal stability during production and have significantly improved water absorption and whitening properties. It is advantageously used to produce transparent products. (Prior art) Vinyl chloride resin for paste used in the preparation of vinyl chloride resin plastisol compositions is prepared by first adding vinyl chloride or a mixture of vinyl chloride and other monomers copolymerizable with vinyl chloride to an aqueous medium. The monomers are subjected to emulsion polymerization using an emulsifier and a water-soluble polymerization initiator, or the monomers are formed into homogeneous oil droplets by mechanical shearing force using an emulsifier and a polymerization initiator that is soluble in the monomers used. A homogeneous aqueous dispersion of a vinyl chloride resin is produced by polymerization using a so-called micro-suspension polymerization method, in which the vinyl chloride resin is dispersed and polymerized, and then the dispersion is spray-dried. A vinyl chloride resin plastisol composition produced using a paste resin produced in this manner contains the emulsifier and all other additives used during polymerization as they are. For this reason, transparent vinyl chloride resin products manufactured using vinyl chloride resin plastisol manufactured by this method, for example, when immersed in water, are free of additives such as emulsifiers used in the manufacture of paste resins. As a result, it easily absorbs water, turns white, and loses its transparency. For example, vinyl chloride foam flooring called cushion flooring is
PVC resin plastisol has the drawback that its transparent skin layer absorbs water and whitens and devitrifies, making printed patterns unclear and discoloring in the form of spots. A composition was needed. In addition, preventing water absorption and whitening of transparent products and improving thermal stability during manufacturing generally require contradictory conditions, and if you try to improve the thermal stability during molding, the water absorption and whitening of the product will become significant. On the other hand, there was a contradiction in that if an attempt was made to reduce water absorption and whitening of the product, the thermal stability during manufacturing and processing would deteriorate. In JP-A-58-76441, a proposal was made to use a vinyl chloride resin for paste containing a phosphate emulsifier in order to prevent water absorption and whitening of resin products using vinyl chloride resin plastisol. However, the water absorption whitening property was not sufficiently improved and the thermal stability during molding was poor. Also, JP-A-55-80445 and JP-A-59-
Publication No. 152941 discloses that in order to improve the thermal stability of halogen-containing resins such as vinyl chloride resins during molding, hydrotalcites, especially BET, are added to the same resins.
It has been proposed to contain hydrotalcites having a specific surface area of 30 m ² /g or less and treated with decrystallization water together with a tin-based stabilizer and stearyl alcohol. However, such proposals only provide the effect of improving thermal stability, and do not mention at all how to simultaneously improve thermal stability and water absorption whitening properties, including the resin used. do not have. (Problems to be Solved by the Invention) The present invention provides a vinyl chloride resin product that can be used in the production of vinyl chloride resin products, particularly transparent products, to obtain products that have excellent thermal stability during manufacturing processing and do not whiten upon water absorption. It is an object of the present invention to provide a resin plastisol composition. (b) Structure of the Invention (Means for Solving the Problems) As a result of repeated research in order to solve the above-mentioned problems, the present inventors have discovered that a vinyl chloride resin can be produced using a fatty acid emulsifier. Moreover, this objective could only be achieved by incorporating hydrotalcites and a liquid composite stabilizer or an organotin stabilizer into a paste vinyl chloride resin with a low total alkali metal content. . That is, the vinyl chloride resin plastisol composition of the present invention contains a fatty acid emulsifier as a main emulsifier and a total alkali metal content of 500 ppm or less. and 0.1 to 5.0 parts by weight of liquid compound stabilizer or organotin stabilizer.
It is characterized in that it is contained in a proportion of 5.0 parts by weight. The vinyl chloride resin for paste used to produce the vinyl chloride resin plastisol composition of the present invention can be produced by the above-mentioned method or a known method such as the method of As for the emulsifier used, it is necessary to use a fatty acid emulsifier as the main emulsifier, and to make sure that the total alkali metal content in the produced paste resin is 500 ppm or less. The vinyl chloride resin for paste used in the present invention may be made of a homopolymer resin of vinyl chloride, or may be made of vinyl chloride and, for example, vinyl acetate, vinyl propionate, methyl acrylate, methyl methacrylate, dibutyl male. ate, diethyl fumarate, vinyl methyl ether, acrylonitrile, methacrylonitrile, ethylene, propylene, styrene, vinylidene chloride, vinyl bromide, etc. do not have. The "fatty acid emulsifier" described herein is a general term for fatty acid emulsifiers and fatty acid salt emulsifiers. The reason why a fatty acid emulsifier is used as the main emulsifier is that vinyl chloride plastisol prepared using a paste resin made using other emulsifiers, such as lauryl sulfate or dodecylbenzene sulfonate, does not whiten due to water absorption. This is because it gives a remarkable resin product. Further, the reason why the total alkali metal content in the paste resin is set to 500 ppm or less is that as the total alkali metal content in the paste resin increases, thermal stability improves, but water absorption whitening becomes significant. The fatty acid emulsifier as the main emulsifier is usually used as a fatty acid salt (in the case of the method described above) or as a free fatty acid (in the case of the method described above). The fatty acid of such a fatty acid emulsifier has an oxygen number of 8 to
20, preferably 8 to 18, and the fatty acid may be used alone or as a mixed fatty acid. Examples of fatty acid salts include alkali metal salts, ammonium salts, and amine salts. However, alkali metal salts are undesirable because they increase the total alkali metal content in the resulting paste resin, and ammonium salts are undesirable. and amine salts, especially ammonium salts are preferred. Even if alkali metal salts are used, the total alkali metal content in the above paste resin must be 500 ppm.
It should be used within a range that does not exceed. In some cases, other emulsifiers can be used in combination with the fatty acid emulsifier, which is the main emulsifier, as long as the amount is relatively small. The amount of the fatty acid emulsifier used is 3% by weight or less, preferably 0.3 to 1.0% by weight of the fatty acid based on the paste resin to be produced. If the amount of the emulsifier is too large, the quality of the vinyl chloride resin product may deteriorate due to bleeding or plateout of fatty acids or fatty acid salts. In addition, in the production reaction of the vinyl chloride resin for paste used in the preparation of the vinyl chloride resin plastisol composition of the present invention, for example, persulfates (sodium salts, potassium salts, ammonium salts, etc.) are used as polymerization initiators. , water-soluble peroxides such as hydrogen peroxide, or these together with sodium sulfite, ammonium sulfite, sodium bisulfite, ascorbic acid, formaldehyde,
A water-soluble redox catalyst consisting of a reducing agent such as sodium sulfoxylate, or an oil-soluble catalyst such as azobisisobutyronitrile, lauroyl peroxide, t-butyl peroxypivalate, etc., or these and the above redox catalyst. A known initiator in combination with a reducing agent for the catalyst is used. However, initiators containing alkali metal salts such as sodium persulfate and potassium persulfate are undesirable because they increase the total alkali metal content in the resulting paste resin, and even if used, the total alkali metal content in the paste resin will increase. content
It should be used within a range of 500ppm or less. The vinyl chloride resin for paste used in the present invention can contain various modifiers that are generally used as modifiers for resins for paste. However, many of these modifiers have a negative effect on water absorption and whitening properties and thermal stability, so the amount of modifiers added should be limited to a small amount of 2% by weight based on the paste resin. is desirable. Examples of modifiers that can be added include higher alcohols, higher fatty acids, and nonionic surfactants. In order to produce the composition of the present invention using the vinyl chloride resin for paste produced as described above, the vinyl chloride resin for paste, hydrotalcites, and a liquid composite stabilizer or an organic tin stabilizer are used. and by dispersing them in a suitable plasticizer using the above-mentioned proportions. As a dispersion method, a method is used in which a predetermined amount of each of the above-mentioned components is weighed and mixed uniformly using a mixer such as a high-speed mixer or a kneader. The "composite stabilizer" described herein is a salt of at least two metal organic acids, such as ricinoleic acid, 2-ethylhexoic acid, naphthenic acid, benzoic acid, and salicylic acid, and is usually a liquid composite stabilizer. It is commercially available as. The liquid composite stabilizers used in the present invention include, for example, barium-zinc stabilizers, magnesium-
Zinc-based, calcium-zinc-based, calcium-barium-based, cadmium-barium-based, barium-zinc-tin-based, cadmium-barium-zinc-based, sodium-zinc-based Examples of organic tin stabilizers include dibutyltin dilaurate, dibutyltin maleate, and dibutyltin mercaptide. Among these stabilizers, those containing alkali metals, such as sodium-zinc stabilizers, have a negative effect on the water absorption and whitening properties of resin products for unknown reasons, so it is not recommended to use them in large amounts. . Particularly preferred liquid composite stabilizers are zinc-based composite stabilizers or Sn-based stabilizers that do not contain alkali metals. The content of the alkali metal-free liquid composite stabilizer in the composition of the present invention is 0.1 to 5.0 parts by weight, preferably 0.15 to 3.0 parts by weight, based on 100 parts by weight of the vinyl chloride paste resin. If the content is too small, thermal stability will be poor, and if it is too large, water resistance cannot be achieved. The hydrotalcites used in the present invention are
It is preferable that the BET specific surface area is 30 m ² /g or less and that it has been treated with decrystallization water. As mentioned above, the content ratio of hydrotalcites is 0.1 to 5.0 parts by weight per 100 parts by weight of the vinyl chloride paste resin.
Preferably it is 0.15 to 3.0 parts by weight. If the content of hydrotalcites is too low, the effect of improving thermal stability due to the addition of hydrotalcites cannot be expected, and if it is too high, the transparency of the resulting product will decrease, which is not preferable. Hydrotalcites may be added at any stage during the production process of the vinyl chloride resin for paste, or may be added during the plastisol preparation process. The vinyl chloride resin plastisol composition of the present invention contains, in addition to the above-mentioned components, a suitable plasticizer as described above, and the composition itself is in the form of a sol. Examples of the plasticizer include phthalate ester plasticizers such as dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, diisodecyl phthalate, butyl lauryl phthalate, ditridecyl phthalate, butyl benzyl phthalate, and butyl phthalyl butyl glycolate. trimellitic acid plasticizers such as tributyl trimellitate, triheptyl trimellitate, trioctyl trimellitate, polyester plasticizers obtained by condensation of polybasic acids and glycols, tricresyl phosphate,
Phosphate ester plasticizers such as trioctyl phosphate, fatty acid ester plasticizers such as tri-n-butyl citrate, dioctyl adipate, dioctyl azelaate, dioctyl sebacate, methyl acetyl ricinoleate, alkyl epoxy stearate, epoxidized large Examples include epoxy plasticizers such as soybean oil. These plasticizers may be used alone or in combination of two or more. The amount of plasticizer used is usually 30 to 120 parts by weight, preferably 40 to 80 parts by weight, based on 100 parts by weight of the vinyl chloride paste resin. The vinyl chloride resin plastisol composition of the present invention may further contain pigments, fillers, antistatic agents, antifogging agents, surface treatment agents, and various other additives. (Examples etc.) Hereinafter, examples of producing resin for paste, examples, and comparative examples will be given and explained in detail. “Department” mentioned in these examples
and "%" are based on weight unless otherwise specified. Paste resin production example A: Put 90 kg of ion-exchanged water at a temperature of 54°C, 12 g of ammonium persulfate, and 75 g of ammonium sulfite into a polymerization tank with a capacity of 200 and equipped with a stirrer, and stir for about 20 minutes to dissolve. Ta. Next, the inside of the polymerization tank was degassed to -610 mmHg and kept at 54°C for 50 minutes. Next, 60 kg of vinyl chloride monomer was charged into the polymerization tank, and the temperature inside the polymerization tank was raised to 50°C. 15 minutes after the monomer was added, it was dissolved in advance.
Approximately 10c.c. of 0.2% ammonium persulfate aqueous solution per minute.
Afterwards, the ammonium persulfate solution was added gradually at a rate of 15%, and the reaction was then carried out while controlling the addition rate of the ammonium persulfate solution to maintain a predetermined polymerization rate. When the polymerization rate reached 15%, the pre-dissolved ammonium myristate solution was added. Start adding a 10% aqueous solution of
The total ammonium myristate was added at a rate of 48 g until the total amount added was 300 g. In the reaction, the pressure inside the tank at 50℃ is 2.0 from the saturation pressure of vinyl chloride monomer.
The process was stopped when the drop in kg/ ^cm2 was reached, and unreacted monomers were collected to obtain a polymer latex. The total amount of the ammonium persulfate aqueous solution added was 4.2. The obtained latex particles have an average particle size of 0.40
The latex was a highly stable latex with monodisperse particles of ±0.01μ. This latex was spray-dried in a conventional manner and then pulverized to obtain about 54 kg of vinyl chloride resin for paste. The polymerization rate was 90%. This paste vinyl chloride resin will be referred to as "resin A" below. Resin A has an alkali metal content of 10 ppm measured by atomic absorption spectrometry.
(calculated value 0), and the content of the fatty acid emulsifier was approximately 0.556% by weight as fatty acids. Production example of resin for paste B In production example A, ammonium persulfate was changed to potassium persulfate, ammonium sulfite was changed to sodium sulfite, and ammonium myristate was changed to sodium lauryl sulfate, but otherwise the process was the same as production example A to produce vinyl chloride for paste. produced resin. The particles of the obtained latex were monodisperse particles with an average particle diameter of 0.50±0.01μ. This latex was spray dried and ground to obtain about 54 kg of vinyl chloride resin for paste. The polymerization rate is
It was 90%. This vinyl chloride resin for paste is called "resin B". Resin B has a calcareous metal content of 570 ppm (calculated value) measured by atomic absorption spectrometry.
553ppm). Paste Resin Production Example C In a polymerization tank with a capacity of 200 and equipped with a stirrer, 80 kg of ion-exchange treated water and the vinyl chloride polymer (seed) containing latex with an average particle diameter of about 0.5 μ obtained in Production Example B above were added. After charging 5.0 kg of polymer and 100 g of sodium metasulfite, it was degassed, then 75 kg of vinyl chloride monomer was charged, and the temperature was raised to 50°C. Thereafter, a total of 10 g of a 0.1% aqueous solution of ammonium persulfate 10 was gradually added at a rate of approximately 13 c.c. per minute, and thereafter the addition rate of the ammonium persulfate solution was adjusted to maintain the predetermined polymerization rate. It was added continuously in a controlled manner. Polymerization rate is 10
% and until the end of the polymerization, add a 10% aqueous solution of ammonium myristate to the total amount of vinyl chloride monomer and seed polymer at a rate of about 0.7% per hour.
0.8 Kg of ammonium myristate was added continuously at a rate of . Polymerization was stopped when the internal pressure of the tank at 50° C. dropped by 2.0 Kg/cm ² from the saturation pressure of vinyl chloride, and unreacted monomers were collected. The total polymerization rate including the seed polymer was 90%. The average particle diameter of the obtained latex was 0.8μ, and the stability of the latex was good. This latex was spray dried according to the conventional method.
It was pulverized to obtain a vinyl chloride resin for paste. This paste resin is called "resin C." Resin C is
The alkali metal content measured by atomic absorption spectrometry was 350 ppm (calculated value 357), and the content of the fatty acid emulsifier was about 1.11% by weight as fatty acids. Manufacturing example of resin for paste D In the above manufacturing example C, ammonium persulfate was changed to potassium persulfate, ammonium myristate was changed to sodium lauryl sulfate, and 30 g of sodium hydrogen carbonate was added when adding the seed polymer latex, and the other steps were as follows. Polymerization was carried out analogously to Example C. The polymerization rate including the seed polymer was 90%, and the average particle diameter of the obtained latex was 0.8μ. This latex was spray dried according to the conventional method.
It was pulverized to obtain a vinyl chloride resin for paste. This paste resin is called "resin D." Resin D has an alkali metal content measured by atomic absorption spectrometry.
It was 1200ppm (calculated value 1155ppm). Paste resin production example E: 100 kg of ion-exchange treated water and lauroyl peroxide are placed in a prepolymerization tank with a capacity of 200 and equipped with a stirrer.
600 g of sodium lauryl sulfate, 400 g of lauryl alcohol, and the inside of the prepolymerization tank was degassed. Then, 60 kg of vinyl chloride monomer was charged and kept at 35° C. for 10 minutes with stirring. Next, the contents of the prepolymerization tank were heated to 250 µm using an emulsifying machine so that the contents became the desired droplet size (average approximately 0.4μ).
The mixture was transferred to a 200-capacity polymerization tank equipped with a stirrer and degassed in advance while undergoing emulsification treatment at a concentration of kg/cm ² . After the transfer was completed, the temperature inside the polymerization tank was raised to 47°C, and the polymerization was completed by a known method. The polymerization rate is
90%, and a latex with good stability was obtained.
The average particle diameter of the polymer particles (seed polymer) in this latex was 0.4±0.01μ. Next, 80 kg of ion-exchanged water and 4.6 kg of the seed latex with an average particle diameter of about 0.4 μ obtained as above were charged as a polymer into a polymerization tank with a capacity of 200 and equipped with a stirrer, and the mixture was heated at 60°C for 2 hours. The amount of lauroyl peroxide in the seed latex was adjusted accordingly. Next, the inside of the polymerization tank was degassed, 75.4 kg of vinyl chloride monomer was charged, and the temperature inside the polymerization tank was raised to 50°C, and then a 0.3% aqueous solution of ammonium sulfite that had been dissolved in advance was gradually added. Polymerization was started. The ammonium sulfite aqueous solution was added continuously while being controlled to maintain a constant polymerization rate. From the time when the polymerization rate reaches 10% until the end of polymerization, add a 10% aqueous solution of ammonium myristate, which has been dissolved in advance as an emulsifier, to the total amount of vinyl chloride monomer and seed polymer. continuously at a rate of approximately 0.7 per hour, and the total weight as ammonium myristate is 0.8
I prepared it to be Kg. When the internal pressure of the polymerization tank decreased from the saturation pressure of the vinyl chloride monomer to 2.0 Kg/cm ² , the polymerization reaction was stopped, and unreacted monomers were collected to obtain a polymer latex. The polymerization rate, including the seed polymer, was 90%, and the average particle size of the latex was 1.0μ. The obtained latex was spray dried and ground to obtain about 72 kg of vinyl chloride resin for paste. This paste resin is called "Resin E". Resin E has an alkali metal content of 40 ppm (calculated value) measured by atomic absorption spectrometry.
38 ppm), and the content of the fatty acid diameter emulsifier was approximately 1.11% by weight as fatty acids. Paste Resin Production Example F A polymer latex was produced in the same manner as Production Example E except that the ammonium myristate used in the main polymerization after addition of seed latex in Production Example E was changed to sodium dodecylbenzenesulfonate. . The polymerization rate was 90%, and the average particle size of the obtained latex was about 1.0μ. This latex was spray dried and ground to obtain about 72 kg of vinyl chloride resin for paste. This paste resin is called "resin F." Resin F had an alkali metal content of 790 ppm (calculated value 772 ppm) as measured by atomic absorption spectrometry. Examples 1 to 10 Comparative Examples 1 to 6 100% of resin A obtained in Production Example A above
1 part, 60 parts of dioctyl phthalate (plasticizer), various stabilizers shown in Table 1, and hydrotalcite were blended in various ratios, and plastisol compositions were prepared according to a conventional method. The initial coloration, thermal stability, and water absorption whitening properties of each of the obtained plastisol compositions were examined using the following test methods. The results were as shown in Table 1. Test method for initial coloration: Plastisol is applied onto aluminum foil to a thickness of 1 mm after heating, and the coating film is coated with 195
The sheet is heated at 195° C. for 5 minutes and then cut out. The sheet is then heated at a temperature of 195° C., taken out every 5 minutes, and the time until it becomes pale yellow colored is determined visually. Thermal stability test method: Continuing the above initial coloring test, red (black)
Visually judge the time until it turns brown. Water absorption whitening test method: A coating film obtained by coating on a glass plate in the same manner as in the initial coloring test was gelled and melted at 195°C for 10 minutes, and then a 1 mm thick sheet was cut out.
After immersing it in hot water at 40℃ for 60 minutes, it was taken out and a light beam with a wavelength of 550mμ was transmitted using a spectrophotometer.
The amount of transmitted light is measured and expressed as light transmittance (%).

【table】

[Table] Comparative Examples 7 to 17 Using the powder of resin B obtained in Production Example B, plastisol was prepared according to the formulation shown in Table 2. The results were as shown in Table 2.

【table】

[Table] Examples 11 to 15 Using the powder of resin E obtained in Production Example E, Table 3
The results of preparing plastisol using the formulation shown in Table 3 are as shown in Table 3.

[Table] Comparative Examples 18 to 22 Using the powder of resin F obtained in Production Example F, Table 4
The results of preparing plastisol using the formulation shown in Table 4 are as shown in Table 4.

【table】

[Table] Examples 16 to 20 Using the powder of resin C obtained in Production Example C, Table 5
Plastisol was prepared using the formulation shown in Table 5. The results are shown in Table 5.

[Table] Comparative Examples 23 to 27 Using the powder of resin D obtained in Production Example D, Table 6
The results of preparing plastisol using the formulation shown in Table 6 are as shown in Table 6.

【table】

[Table] Examples 21-25 Comparative Examples 28-29 Polymer latex obtained in Production Example E
NaOH was added to bring the total alkali metal content in the resin after spray drying to the values listed in each example in Table 7. Using each resin powder obtained in this way,
Plastisol was prepared according to the formulation shown in Table 7.
The results were as shown in Table 7.

[Table] (c) Effects of the Invention The vinyl chloride resin plastisol composition of the present invention provides a vinyl chloride resin product with excellent water absorption and whitening properties in a well-balanced manner.

Claims (1)

[Claims] 1. 0.1 to 5.0 parts by weight of hydrotalcites per 100 parts by weight of a vinyl chloride resin for paste containing a fatty acid emulsifier as the main emulsifier and having a total alkali metal content of 500 ppm or less. and a liquid composite stabilizer or an organic tin stabilizer in a proportion of 0.1 to 5.0 parts by weight. 2 The fatty acid emulsifier as the main emulsifier has 8 to 18 carbon atoms.
The composition according to claim 1, which is a fatty acid emulsifier containing 0.3 to 1.0% by weight of fatty acids based on the vinyl chloride resin for paste. 3. Claim 1, wherein the liquid composite stabilizer is a zinc-based composite stabilizer that does not contain an alkali metal.
or the composition according to item 2.