JPH0315938B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for flame-retardant halogen-containing vinyl resin, and more specifically, by using an antimony pentoxide-based flame retardant and a zinc-based stabilizer in combination, halogen-containing vinyl resin, typified by vinyl chloride resin, can be made flame-retardant. This invention relates to a method for making resin flame retardant without impairing its transparency and thermal stability. Halogen-containing vinyl resin itself has excellent flame retardancy, but for example, so-called soft vinyl chloride resin plasticized with a plasticizer such as dioctyl phthalate, or halogen-containing vinyl resin blended with flammable resin, can easily burn. do. Soft PVC products such as leather, canvas, electric wires, films, and sheets that are widely used as automobile interior materials, electrical/electronic parts, and construction materials, as well as hard PVC products containing impact reinforcement materials, are particularly difficult to twist. ization is essential. Various flame retardants are used to make these resins flame retardant. Antimony trioxide (Sb ₂ O ₃ ),
Inorganic substances such as sodium antimonate, aluminum hydroxide, zirconium oxide, zinc borate, and borax, and organic compounds such as tricresyl phosphate, trichloroethyl phosphate, and chlorinated paraffin are used. In rare cases, organic bromine flame retardants are also used. These have advantages and disadvantages in terms of flame retardancy, transparency, thermal stability, weather resistance, cold resistance, and bleed/bloom resistance. Antimony trioxide usually has a particle size of about 0.5 to 10μ, has a large refractive index, and has a low light transmittance, so it has extremely strong hiding properties and completely loses its transparency, which is the most important characteristic of halogen-containing vinyl resins. I get tired. Also, when coloring for its concealing properties,
It has drawbacks such as requiring a large amount of pigment and being limited in the types of colors that can be obtained. In order to improve this drawback, the particle size was made extremely small (Special Publications Publication No. 46).
-7170), it has been proposed to increase the particle size by forming a single crystal. All of these methods are used to improve light transmittance, and the former method significantly improves transparency, but adding pigments increases hiding power and increases the thermal stability of the resin. In addition, the latter method does not provide sufficient transparency. Antimony pentoxide is an antimony-based flame retardant that can be applied to halogen-containing vinyl resins without losing the transparency of the resin. (J.Coated Fabric, Vol 11.P137, 1982) This is antimony pentoxide sol (particle size 20-100mμ)
It is powdered by spray drying etc. and is antimony pentoxide tetrahydrate. This antimony pentoxide tetrahydrate has a small refractive index and is a very small primary particle, so it has a high light transmittance and has very good transparency. However, this antimony pentoxide has a defect that significantly deteriorates the thermal stability of the resin (see Comparative Example). To compensate for this deficiency, the use of Ba-Cd-Zn stabilizers or tin mercaptide stabilizers has been proposed (J.
Coated Fabric Vol 11.P137, 1982). However, the former cannot be used practically because of the toxicity of cadmium and the occurrence of bleed bloom, while the latter has poor weather resistance. Sodium antimonate has a small flame retardant effect when the particle size is large, but after pulverizing it to 0.1 to 8μ and partially neutralizing it with acid, it shows good transparency, flame retardancy, and thermal stability. It has been reported (Special Publication No. 47-36863). However, if the primary particle size is in this range, sufficient transparency cannot be obtained, and since this neutralization is partial neutralization, most of the content is sodium antimonate, so sufficient flame retardance cannot be obtained. Inorganic substances such as aluminum hydroxide, zirconium oxide, zinc borate, and borax have inferior flame retardant effects compared to antimony trioxide and antimony pentoxide, and also lose transparency in the same way as antimony trioxide.
Phosphorous plasticizers such as tricresyl phosphate, which have a plasticizing effect without losing transparency, and chlorinated paraffins have a flame retardant effect inferior to that of antimony trioxide, so they must be added in large amounts. As a result, it tends to bleed and has poor cold resistance. In other words, conventional products and techniques do not impair transparency, which is the most important feature of halogen-containing vinyl resin.
In addition, it has not been possible to achieve economical flame retardancy while satisfying physical properties such as thermal stability. The present inventors have completed the present invention as a result of extensive research into flame retardant methods that do not have the above-mentioned drawbacks. That is, the present inventors have developed various methods to take advantage of the characteristic that antimony pentoxide does not impair the transparency of the resin when applied to halogen-containing vinyl resin, while overcoming the disadvantage that it worsens the thermal stability of the resin. I conducted research. Unlike antimony trioxide, antimony pentoxide is a fairly strong solid acid, so it can be used for Na, Mg, Ca,
It has the property of strongly binding with basic and amphoteric substances containing Sr, Ba, Zn, Cd, Pb, etc. Therefore, when antimony pentoxide is applied directly as a flame retardant to plasticized halogen-containing vinyl resin, , reacts with metal soap stabilizers commonly used in these, such as zinc stearate, barium stearate, magnesium stearate, etc., so that the function as a stabilizer is significantly reduced. It is assumed that this deteriorates the thermal stability of the plasticized halogen-containing vinyl resin and causes discoloration and bleed/bloom phenomena. Based on the above facts and inferences, the present inventors first added Na, Ca, Mg to antimony pentoxide colloid.
Various basic metals such as Ca, Ba, Nn, Al, and Sb () are added in the form of hydroxides, each singly or in combination, and applied to plasticized halogen-containing vinyl resin to stabilize its thermal stability. The sex was measured. As a result, they found that a combination of alkali metals and alkaline earth metals is effective. Furthermore, it has been found that adding a small amount of phosphorus in the form of phosphoric acid to the basic metal has a significant additive effect in terms of improving thermal stability. Furthermore, regular Ba-Zn is used as a stabilizer.
It has been found that initial coloring can be significantly reduced by adding zinc organic monocarboxylate as a zinc-based stabilizer in addition to the system stabilizer. The present invention has been made based on the above-mentioned findings. That is, (A) the alkali metal is expressed by the general formula M ₂ O (M=
3 to 18% by weight as Na, K), (B) 2 to 20% by weight of alkaline earth metal as general formula M'O (M'=Mg, Ca, Sr, Ba), (C) phosphoric acid and/or Contains 0.5 to 3% by weight of an alkali phosphate salt as P ₂ O ₅ , and (D) the remainder consists essentially of four components of antimony pentoxide, and has a molar ratio of (M ₂ O + M′O)/Sb ₂ O ₅ is 0.5~1.2,
The M ₂ O/M′O ratio is also 0.5 to 5.0 in molar ratio and
An antimony pentoxide flame retardant having a P ₂ O ₅ /(M ₂ O + M′O) ratio of 0.02 to 0.2 by weight and a zinc organic monocarboxylate having 6 to 24 carbon atoms are mixed into The present invention relates to a method for flame retardant halogen-containing vinyl resin, characterized in that an antimony oxide flame retardant is used in combination in a weight ratio of 0.05 to 0.5. The antimony pentoxide used in the present invention is obtained by the method of oxidizing antimony trioxide (Japanese Patent Publication No. 1983-
11848), by dealkalizing alkali antimonate with an ion exchange resin (US Patent No. 4110247)
Antimony pentoxide sol and sodium antimonate with a primary particle size of 5 to 100 mμ produced by other methods are treated with acid to obtain a primary particle size of 200 mμ.
The following antimony pentoxide sol or antimony pentoxide suspension. Note that all of these antimony pentoxides have a tetrahydrate. The flame retardant used in the present invention is an antimony pentoxide sol or antimony pentoxide suspension containing the above-mentioned antimony pentoxide colloid, an alkali metal hydroxide (NaOH, KOH), a soluble salt of an alkaline earth metal (MgCl ₂ , CaCl ₂ , BaCl ₂ etc.), and alkaline earth metal hydroxides (Mg(OH) ₂ , Ca
(OH) ₂ , Ba(OH) 2.8H ₂ O _, etc.), and then phosphoric acid and/or an alkali phosphate salt (Na, K, NH ₃ as an alkali salt) was added and mixed. It can be manufactured by separating, drying, and pulverizing things. The alkali metal compound and the like can be added at room temperature to 100° C., and strong stirring such as in a disper is preferable. Antimony pentoxide used in the present invention is a strong cation exchanger (Japanese Patent Publication No. 45-6695). For this reason,
It strongly adsorbs the added alkali metal ions and alkaline earth metal ions and incorporates them into the structure. Therefore, the cation exchange ability of antimony pentoxide can be blocked by adding an alkali metal hydroxide or alkaline earth metal salt and hydroxide to the antimony pentoxide sol and antimony pentoxide suspension. And (M ₂ O + M′O)/Sb ₂ O ₅
Even if the molar ratio is 0.8 or more, it retains the structure of antimony pentoxide tetrahydrate and does not become a sodium or potassium antimonate structure.
In addition, when using MgCl ₂ , CaCl _{2 ,} etc., unnecessary ions such as chlorine cause a decrease in thermal stability and must be removed by deionization and washing with an anion exchange resin. Among the hydroxides of alkaline earth metals, only barium hydroxide has a high solubility, so ion exchange and washing are unnecessary, making it particularly effective. As mentioned above, by adding an alkali or alkaline earth metal compound, the antimony pentoxide sol is micro-agglomerated to become a modified antimony pentoxide slurry. Spray the resulting slurry with a dryer,
Flame retardant powder can be obtained by directly drying with a drum dryer or the like, or by separating the slurry by suction filtration, centrifugal filtration, etc., drying the cake, and then pulverizing it with a pin disk mill, a jet-ohmizer, etc. The obtained flame retardant was mixed with a halogen-containing vinyl resin, a plasticizer, and a Ba-Zn stabilizer in a Henschel mixer, and then mixed with two rolls at 170°C to a thickness of 0.7 to 0.8 mm.
A mastication sheet was prepared. The gear oven method was adopted as a test method for the thermal stability of this sheet. The oven temperature was set at 175°C, and thermal stability was evaluated based on the time taken for the test piece to blacken and the degree of initial coloration. According to the above test method, even if antimony pentoxide powder containing the above alkali and alkaline earth metals is used, the initial coloration cannot be sufficiently reduced as long as a normal Ba-Zn stabilizer is used. By using the flame retardant and zinc stabilizer shown below in combination, initial coloring could be significantly reduced. When alkali and alkaline earth metals are added to antimony pentoxide, the initial coloring decreases and the blackening time conversely decreases in the following order: alkali metal alone, a mixture of alkali metal and alkaline earth metal, and alkaline earth metal alone. In order to satisfy both initial coloring and blackening time, it is best to mix alkali metals and alkaline earth metals, and the amount of alkali metals in the flame retardant is 3 to 3, assuming the general formula _M2O (M=Na, K). 18% by weight, alkaline earth metals with the general formula M′O (M′=Mg, Ca,
Contains 2 to 20% by weight as Sr, Ba), and
MO/M′O ratio is 0.5 to 5.0 in molar ratio, preferably 1.0 to
It is 3.0. If it is 5.0 or more, the initial coloring prevention effect will be small, and if it is 0.2 or less, the blackening time will be shortened. On the other hand, the molar ratio of M ₂ O and M'O to Sb ₂ O ₅ is preferably (M ₂ O+M'O)/Sb ₂ O ₅ of 0.5 to 1.2. If it is less than 0.5, it is insufficient to suppress the ion exchange ability of Sb ₂ O ₅ , and if it is more than 1.2, excess base will remain and the basicity will become extremely strong, promoting the dehydrochlorination effect of halogen-containing vinyl resin. This may cause initial discoloration. The addition of phosphoric acid and/or an alkali phosphate salt has a particularly remarkable effect on preventing initial discoloration.
Or 0.5 alkali phosphate salt as P ₂ O ₅ in flame retardant.
Contains ~3% by weight, and P ₂ O ₅ /(M ₂ O + M′O)
The ratio is preferably 0.02 to 0.2 by weight. If it exceeds 0.2, the amount of phosphoric acid and/or alkali phosphate added becomes too large, resulting in decreased transparency. If it is less than 0.02, the initial coloring prevention effect will be reduced. The zinc stabilizer that can be used in the present invention is a zinc salt of an organic monocarboxylic acid having 6 to 24 carbon atoms, such as zinc caprate, zinc stearate, zinc laurate, zinc oleate, etc. It's salt. The amount added is such that the ratio of zinc stabilizer/the flame retardant is 0.05 to 0.5 by weight. If it is less than 0.05, the edge coloration cannot be sufficiently reduced, and if it is more than 0.5, the blackening time will be significantly shortened due to zinc burning. In the present invention, the above-mentioned flame retardant and zinc stabilizer can be blended with a halogen-containing vinyl resin together with a plasticizer such as dioctyl phthalate, a Ba-Zn stabilizer, and an additive such as epoxidized soybean oil using a known method. For example, mix a halogen-containing vinyl resin, a powder stabilizer, a zinc stabilizer, and a flame retardant, and while stirring with a Henschel mixer, add a liquid stabilizer and dioctyl phthalate (DOP) in which epoxy soybean oil has been dissolved in advance. The mixture is mixed until the temperature reaches 105-115°C. In the present invention, halogen-containing vinyl resin means vinyl chloride resin and copolymers thereof. Copolymers with vinyl chloride resins include copolymers with ethylene, propylene, vinylidene chloride, vinyl acetate, vinyl alcohol, acrylic esters, methacrylic esters, styrene, acrylonitrile, etc., and vinyl chloride graft copolymers. Examples include graft copolymers of polystyrene with vinyl acetate, polyesters, polyurethanes, polystyrene, and the like. A copolymer as used herein refers to a polymer containing two or more types of monomers. The method of the present invention is a flame retardant method for a halogen-containing vinyl resin that does not impair the transparency of the halogen-containing vinyl resin and does not deteriorate its thermal stability and cold resistance. EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto.
The test methods adopted in the following examples are as follows, and the percentages in the compositions in Examples and Comparative Examples indicate weight percent. Flame retardancy test: A 3.0mm thick press sheet was prepared and tested in accordance with the vertical test method of UL-94 method. Bleeding test: The test sheet was left at 80° C. and 99% humidity for 7 days, and visually observed to see if liquid oozed out onto the surface of the 1.00 mm thick press sheet. Initial coloring property: The color difference due to reflected light of a 1.00 mm thick press sheet was measured, and the coloring property was indicated by the YI value (yellow value). Transparency: The transmittance (L value) of a 1.00 mm thick press sheet by transmitted light was measured. Examples 1 to 5 and Comparative Examples 1 to 2 a) Production of flame retardants Flame retardants were produced using the formulations shown in Table 1 using the three methods described below. The antimony pentoxide sol used was manufactured by the ion method.
The composition is 10% Sb ₂ O ₅ and 0.57% Na ₂ O. ) Antimony pentoxide sol (Sb ₂ O ₅ 10%) with a particle size of 40 to 70 mμ, 10% NaOH aqueous solution, 4
%Ba(CH) ₂・_8H2O aqueous solution, and ₁₀ % _H3PO4
The aqueous solutions were added in the proportions shown in Table 1, and after stirring at room temperature for about 4 hours, the obtained micron aggregates of antimony pentoxide were filtered off by suction filtration, and the obtained wet cake was dried at 120 ° C. It was then crushed with a Jet-Omizer. The average particle size of the pulverized product was 1μ. ) 10% NaOH aqueous solution in antimony pentoxide sol (Sb ₂ O ₅ 10%) with a particle size of 20-50 mμ, 10
% CaCl ₂ aqueous solution and 10% H ₃ PO ₄ aqueous solution were added in the proportions shown in Table 1, and after stirring at room temperature for about 2 hours, a predetermined amount of anion exchange resin was added and chlorine ions were removed. The resin and the slurry were separated, and the resulting micron aggregates of antimony pentoxide were filtered off by suction filtration, and the resulting wet cake was dried at 150° C. and then ground in a pin disc mill. The average particle size of the pulverized product was 2.5μ. ) 10% NaOH aqueous solution in antimony pentoxide sol (Sb ₂ O ₅ 10%) with a particle size of 80-100 mμ, 10
% MgCl ₂ aqueous solution and 10% H ₃ PO ₄ aqueous solution in the proportions shown in Table 1, and after stirring at room temperature for about 3 hours, the obtained micron aggregates of antimony pentoxide were separated by suction filtration. The resulting wet cake was dried at 140-180°C, and then pulverized using a high-speed mixer. The average particle size of the pulverized product was 5μ. (Production of flame retardant of comparative example) Comparative example 1 150 g of 10% NaOH aqueous solution was added to 1200 g of antimony pentoxide sol (Sb ₂ O ₅ 10%) with a particle size of 40 to 70 mμ, and after stirring at room temperature for about 4 hours, The obtained antimony pentoxide slurry was evaporated to dryness at 130°C and ground in a pin disc mill. The average particle size of powder products is
It was 3.5μ. Comparative Example 2 1800 g of 4% Ba(OH) 2.8H _{2 O} aqueous solution was added to 720 g of antimony pentoxide sol (Sb ₂ O ₅ 10%) with a particle size of 20 to 50 mμ, and after stirring at room temperature for 3 hours, the obtained The resulting antimony pentoxide slurry was filtered, and the resulting cake was dried at 150° C. and then ground in a pin disc mill. The average particle size of the powder product was 2.5μ.

【table】 Table 2 on the next page shows the composition of the flame retardant.

【table】

[Table] b) Evaluation of flame retardants The seven types of flame retardants obtained in a), and as comparative examples, antimony pentoxide of Comparative Example 3 (spray-dried product of antimony pentoxide sol), Comparative Example 4
A sheet was prepared according to the formulation shown in Table 3 below by adding antimony trioxide, and its thermal stability, transparency, and flame retardance were evaluated.

【table】

[Table] The above compound was mixed for 10 minutes using a high-speed mixer (Hensiel mixer), and when the temperature rose to 105-115℃, the mixing was stopped and the mixture was rapidly cooled to room temperature. The mixture was mixed at 170° C. for 5 minutes, and a sheet with a thickness of 0.7 to 0.8 mm was prepared and subjected to a thermal stability test. In addition, press sheets of 1.0 mm and 3.0 mm thickness were prepared by pressing the above sheets as they were or stacking several sheets at 180°C for 6 minutes, and the sheets were tested for transparency, initial coloration, flame retardancy, and bleedability. provided. The results are shown in Table 4.

【table】

[Table] As shown in Table 4, the vinyl chloride sheet obtained by the method of the present invention is an antimony pentoxide-based flame retardant shown in the comparative example in terms of transparency, thermal stability, initial coloring property, flame retardance, etc. and sheets using antimony trioxide.

Claims (1)

[Claims] 1 (A) Alkali metal with the general formula M ₂ O (M=Na, K)
(B) 2 to 20% by weight of an alkaline earth metal with the general formula M′O (M′=Mg, Ca, Sr, Ba), (C) phosphoric acid and/or an alkali phosphate salt. _{P2O5 _}
0.5 to 3% by weight, and (D) the remainder consists of the four components of antimony pentoxide, and the molar ratio (M ₂ O + M′O)/Sb ₂ O ₅ is 0.5 to 1.2, M ₂ O／
The M′O ratio is also 0.5 to 5.0 in molar ratio and P ₂ O ₅ /
An antimony pentoxide flame retardant having a (M ₂ O + M′O) ratio of 0.02 to 0.2 by weight and a zinc organic monocarboxylate having 6 to 24 carbon atoms are mixed into
The weight ratio of antimony pentoxide flame retardant is 0.05~
A method for flame retardant halogen-containing vinyl resin, characterized in that it is used in combination within a range of 0.5.