CN102604291A - Halogen-free flame-retardant polyvinyl alcohol foam material and preparation method thereof - Google Patents

Abstract

The halogen-free flame-retardant polyvinyl alcohol foam material disclosed by the invention and its preparation method are composed of 100 parts of polyvinyl alcohol, 20-35 parts of nitrogen-phosphorus halogen-free flame retardant, 0.1-10 parts of catalyst and 0.1-10 parts of nucleation Add the composite powder to the mixed solution consisting of 0.1-10 parts of surfactant, 0.1-10 parts of cross-linking agent and 30-45 parts of plasticizing foaming agent at 60-80 °C Fully swollen, then continuously extruded and foamed at a melting temperature of 140-180°C and a pressure of 8-10 MPa. The limiting oxygen index of the halogen-free flame-retardant polyvinyl alcohol foam material provided by the invention can reach 36%, and the vertical combustion can reach the level of UL94-V0. The pore density of the material can be widely used in heat insulation, sound insulation, shock absorption, packaging, sports equipment, clothing back pads, shoe soles, sofas and cushions, etc. In addition, continuous extrusion and foaming are adopted, so that the preparation process is simple, the cost is low, the environment is friendly, and it is suitable for large-scale industrial production.

Description

Halogen-free flame-retardant polyvinyl alcohol foam material and preparation method thereof

technical field

The invention belongs to the technical field of polyvinyl alcohol foam material and its preparation, and in particular relates to a halogen-free flame-retardant polyvinyl alcohol foam material and a preparation method thereof. the

Background technique

The foam material is a porous composite material with a polymer resin matrix as the main body and numerous cells inside. Due to the characteristics of light weight, sound insulation, heat insulation, cushioning, high specific strength, large adjustable range of physical properties, and simple molding process, foam materials have been widely used in industry, agriculture, daily use, medical treatment, construction, transportation , military, aerospace and other fields, and is becoming an irreplaceable structural or functional material. the

In theory, almost all kinds of polymer resins can be made into foam materials through suitable foam molding process, but due to the influence of foam molding technology, there are only a few kinds of large-scale production and application at present, and they are limited to non-polar Or weakly polar resins, such as polystyrene (PS), polyolefin (PP, PE), polyurethane (PU), etc., greatly limit the application fields of foam materials. In addition, since most polymer resins are composed of hydrocarbons and are flammable, polymer foam materials with a porous structure are not only more flammable, but also release a large amount of toxic and harmful gases during combustion, seriously damaging Personal and property safety. Therefore, it is of great significance to develop flame-retardant polymer foam materials, especially flame-retardant foam materials used in mattresses, sofas, furniture packaging cushions, lightweight concrete blocks, and building energy-saving insulation, which are closely related to personal and property safety. the

As a water-soluble polymer material, polyvinyl alcohol (PVA) not only endows it with strong polarity, high melting point, heat resistance, antistatic, biocompatibility, solvent resistance, etc. characteristics, and it is also a synthetic polymer material that can be completely biodegradable. In addition, polyvinyl alcohol can also be prepared through non-petroleum routes. Therefore, in today's increasingly scarce petroleum resources, it is necessary to vigorously develop polyvinyl alcohol-related materials, including high performance, The multifunctional polyvinyl alcohol polar foam material has more important significance. At present, polyvinyl alcohol foam is mainly produced by solution mechanical or chemical foaming, but the solution process is complex, the production cycle is long, and the production cost is high. Our research group has successfully prepared polyvinyl alcohol polar foam material (CN101153089B) by using water as plasticizer and physical blowing agent through melt molding process. Although this technology provides a new way to produce high-performance, multi-functional, low-cost polyvinyl alcohol polar foams, the limiting oxygen index of the prepared polyvinyl alcohol foams is extremely low (LOI value is about 19), It is extremely flammable, which greatly limits the application fields of polyvinyl alcohol foam materials. the

As a flame-retardant polymer foam material, it can be divided into two types: intrinsic type or additive type. Among them, intrinsic flame-retardant foam materials require the foam matrix itself to be flame-retardant, and the number of such polymer materials is limited. At present, only the melamine foam material of BASF in Germany has been successfully developed and applied. However, such melamine foam materials still have problems such as formaldehyde release, difficult coordination of modulus and flame retardancy, high brittleness, high price, and monopolized production. Additive flame retardant foam materials, such as weakly polar polyurethane foam, will produce droplet phenomenon during combustion and release a large amount of hydrogen cyanide, nitrogen oxides, and isocyanide, regardless of whether the flame retardant is modified or not. Toxic and harmful substances such as acid compounds can seriously threaten personal and property safety. the

Existing methods for halogen-free flame-retardant polyvinyl alcohol, such as Sichuan University Wang Yuzhong et al., prepared halogen-free flame-retardant polyethylene by blending ammonium polyphosphate, layered double metal hydroxide and polyvinyl alcohol in solution. Alcohol; In addition, they also blend ammonium polyphosphate, metal chelate and polyvinyl alcohol in solution to prepare halogen-free flame-retardant polyvinyl alcohol (CN101058730A; Wang D.L.et al./Polymer Degradation and Stability 92(2007) 1555-1564; Zhao C.X.et al./Polymer Degradation and Stability 93(2008) 1323-1331); Another example is that Xu Jianjun of Sichuan University and others co-polymerized phosphate ester flame retardants, various additives and polyvinyl alcohol in a solution Mix the spinning stock solution, and prepare the halogen-free flame-retardant high-strength polyvinyl alcohol fiber (CN102002770A) by wet spinning; another example is that Xia Yanzhi of Qingdao University and others prepared polyvinyl alcohol/silica flame-retardant fiber by solution method (CN101343781A; CN101343782A). However, the halogen-free flame-retardant polyvinyl alcohol materials prepared by these methods are neither halogen-free flame-retardant polyvinyl alcohol foam materials, and the flame retardants used have poor affinity with the polyvinyl alcohol matrix, and the precipitation phenomenon is serious. It is realized by solution blending, so there are problems such as complex preparation process, high cost, and difficulty in realizing continuous large-scale production. the

Contents of the invention

The object of the present invention is to solve the problems existing in the prior art, firstly provide a kind of halogen-free flame-retardant polyvinyl alcohol foam material, this halogen-free flame-retardant polyvinyl alcohol foam material adopts commercialized, low-cost raw materials, through improved It is obtained by foaming in continuous extrusion molding process. the

Another object of the present invention is to provide a method for preparing the above-mentioned halogen-free flame-retardant polyvinyl alcohol foam material. the

The invention provides a halogen-free flame-retardant polyvinyl alcohol foam material, which is characterized in that the foam material is obtained by melting and foaming the following components in parts by weight:

And the limiting oxygen index of the foam material is 28-36% according to the ASTM D2863 standard test, and the vertical combustion is UL94V0 grade according to the ASTM D3801 standard test. the

The polyvinyl alcohol in the above-mentioned halogen-free flame-retardant polyvinyl alcohol foam material is any one of a degree of polymerization of 500-2400 and a degree of alcoholysis of 88-99%, preferably a degree of polymerization of 1700 and a degree of alcoholysis of 99%. The nitrogen-phosphorus halogen-free flame retardant is a series of derivatives formed by melamine and phosphoric acid, preferably any one of melamine phosphate, melamine polyphosphate or melamine pyrophosphate. The plasticizing foaming agent is a mixture of water and any one of ethanol, ethylene glycol, glycerol, pentaerythritol or sorbitol in a weight ratio of 1:1 to 5:1. The catalyst is a compound capable of catalyzing the dehydration of polyvinyl alcohol into carbon, preferably any one of alumina, magnesia, phosphomolybdate, aluminosilicate, molybdosilicate, 4A molecular sieve, hydrotalcite or montmorillonite. The nucleating agent is a compound that can promote the heterogeneous nucleation of the polyvinyl alcohol foam material, preferably any one of talcum powder, calcium carbonate, silicon dioxide or zinc oxide; the surfactant is a compound that can reduce the free energy of the gas-liquid-solid interface , preferably any one of alkyl sulfate, alkyl sulfonate, stearate, siloxane or fluorocarbon surfactant; the crosslinking agent is a compound that can promote the crosslinking reaction of polyvinyl alcohol, preferably boric acid or borax. the

The preparation method of the above-mentioned halogen-free flame-retardant polyvinyl alcohol foam material provided by the present invention is characterized in that the process steps and conditions of the method are as follows:

(1) First add 100 parts of polyvinyl alcohol, 20-35 parts of nitrogen-phosphorus halogen-free flame retardant, 0.1-10 parts of catalyst, and 0.1-10 parts of nucleating agent into a high-speed mixer and mix to make a composite powder. Then add 0.1-10 parts of surfactant and 0.1-10 parts of cross-linking agent to 30-45 parts of plasticizing foaming agent to prepare a mixed solution, and then add the composite powder into the mixed solution to fully swell at 60-80°C;

(2) The fully swollen composite powder is continuously extruded and foamed at a melting temperature of 140-180° C. and a pressure of 8-10 MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. the

Wherein the polyvinyl alcohol used in the method is any one of a degree of polymerization of 500-2400 and a degree of alcoholysis of 88-99%, preferably a degree of polymerization of 1700 and a degree of alcoholysis of 99%. The nitrogen-phosphorus halogen-free flame retardant is a series of derivatives formed by melamine and phosphoric acid, preferably any one of melamine phosphate, melamine polyphosphate or melamine pyrophosphate. The plasticizing foaming agent is a mixture of water and any one of ethanol, ethylene glycol, glycerol, pentaerythritol or sorbitol in a weight ratio of 1:1 to 5:1. The catalyst is a compound capable of catalyzing the dehydration of polyvinyl alcohol into carbon, preferably any one of alumina, magnesia, phosphomolybdate, aluminosilicate, molybdosilicate, 4A molecular sieve, hydrotalcite or montmorillonite. The nucleating agent is a compound that can promote heterogeneous nucleation of the polyvinyl alcohol foam material, preferably any one of talcum powder, calcium carbonate, silicon dioxide or zinc oxide; the surfactant is a compound that can reduce the free energy of the gas-liquid-solid interface , preferably any one of alkyl sulfate, alkyl sulfonate, stearate, siloxane or fluorocarbon surfactant; the crosslinking agent is a compound that can promote the crosslinking reaction of polyvinyl alcohol, preferably boric acid or borax. the

Compared with the prior art, the present invention has the following positive effects:

1) Since the polyvinyl alcohol foam material provided by the present invention contains a halogen-free flame retardant, and is continuously extruded and foamed through melting, it not only realizes the halogen-free flame retardancy of the polyvinyl alcohol foam material for the first time, but also makes the foam material Combining the advantages of polyvinyl alcohol foam materials and halogen-free flame retardant properties, it can greatly expand the application field of polyvinyl alcohol foam materials, and the preparation process of melt continuous extrusion foaming is simple, low cost, and environmentally friendly, suitable for large-scale industrial production . the

2) Because the inventive method is to use commercialization, low cost, environment-friendly phosphate compound containing melamine and its derivatives as the halogen-free flame retardant of polyvinyl alcohol foam material, in addition therein also add char-forming catalyst, thus both The flame retardant performance of the polyvinyl alcohol foam material is greatly improved, and it has the advantages of environmental protection, low price and sustainable development. the

3) Since the inventive method starts from raw material composition and processing technology, by adding flame retardant and various solid-phase processing aids, the nucleation point in the foaming process has been increased, and the cell density of the foam material has been improved (see attached Figures 1 and 2), and by adding surfactants, the dispersibility of various fillers in the polyvinyl alcohol matrix is improved, including the affinity between the flame retardant and the polyvinyl alcohol matrix, which reduces the gap between phases in the foaming process. The interfacial energy improves the heterogeneous nucleation efficiency in the foaming process, thereby overcoming the problems encountered in the preparation of polyvinyl alcohol foam materials by melting processing, such as large foam pore size, uneven size distribution, easy foam collapse, and shape Difficult to control, stable production and low level of continuous production, easy to achieve continuous, efficient and economical industrial production. the

Description of drawings

Fig. 1 is the scanning electron micrograph of the polyvinyl alcohol foam material prepared by existing melt processing technology;

Fig. 2 is the scanning electron micrograph of the polyvinyl alcohol foam material prepared by the method of the present invention. the

Detailed ways

The present invention is described in detail by the following examples, it is necessary to point out that the following examples are only used to further illustrate the present invention, and can not be interpreted as limiting the protection scope of the present invention, those skilled in the art can make according to the present invention Some non-essential improvements and adjustments. the

It is worth noting that the limiting oxygen index of the following examples is tested according to the ASTM D2863 standard, and the vertical combustion is tested according to the ASTM D3801 standard. the

Example 1

Mix 100 parts of polyvinyl alcohol 0588, 20 parts of melamine phosphate, 0.1 part of hydrotalcite and 0.1 part of calcium carbonate in a high-speed mixer to make a composite powder; dissolve 0.1 part of borax and 0.1 part of sodium lauryl sulfate In 30 parts of plasticizing foaming agent (water: ethanol = 5: 1), it is formulated into a mixed solution; the above-mentioned composite powder is added in the mixed solution, and after mixing, it is sealed and stored in a constant temperature oven at 60°C to fully swell; The swollen compound is continuously extruded and foamed by a screw extruder at a melting temperature of 140° C. and a pressure of 8 MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 28%, and the vertical burning is UL94-V0 level. the

Example 2

Mix 100 parts of polyvinyl alcohol 1799, 30 parts of melamine polyphosphate, 3 parts of sodium aluminosilicate and 3 parts of zinc oxide in a high-speed mixer to make a composite powder; dissolve 3 parts of boric acid and 3 parts of silicone oil in 40 parts Plasticizing foaming agent (water: ethylene glycol = 5: 1) to prepare a mixed solution; add the above-mentioned composite powder to the mixed solution, mix well and seal and store in a constant temperature oven at 70°C to fully swell; fully swell The final compound is continuously extruded and foamed by a screw extruder at a melting temperature of 160° C. and a pressure of 9 MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 32%, and the vertical burning is UL94-V0 level. the

Example 3

Mix 100 parts of polyvinyl alcohol 2499, 35 parts of melamine pyrophosphate, 10 parts of 4A molecular sieve and 10 parts of talcum powder in a high-speed mixer to make a composite powder; mix 10 parts of boric acid and 10 parts of sodium dodecylsulfonate Dissolve in 45 parts of plasticizing foaming agent (water: glycerol = 1: 1) to prepare a mixed solution; add the above-mentioned composite powder into the mixed solution, mix well, seal and store in a constant temperature oven at 80°C to fully swell; Continuously extrude and foam the fully swollen compound through a screw extruder at a melting temperature of 180°C and a pressure of 10 MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 36%, and the vertical burning is UL94-V0 level. the

Example 4

Mix 100 parts of polyvinyl alcohol 1799, 25 parts of melamine phosphate, 1 part of sodium phosphomolybdate and 1 part of calcium carbonate in a high-speed mixer to make a composite powder; mix 1 part of borax and 1 part of FC-100 fluorocarbon surface The active agent was dissolved in 35 parts of plasticizing foaming agent (water: glycerol = 2:1) to prepare a mixed solution; the above composite powder was added to the mixed solution, and after mixing, it was sealed and stored in a constant temperature oven at 65°C Fully swell; continuously extrude and foam the fully swollen compound through a screw extruder at a melting temperature of 150°C and a pressure of 8.5MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 30%, and the vertical burning is UL94-V0 level. the

Example 5

Mix 100 parts of polyvinyl alcohol 1799, 30 parts of melamine phosphate, 5 parts of sodium molybdate and 5 parts of silicon dioxide in a high-speed mixer to make a composite powder; mix 5 parts of borax and 5 parts of dodecyl Dissolve sodium sulfate in 40 parts of plasticizing foaming agent (water: glycerol = 3:1) to prepare a mixed solution; add the above-mentioned composite powder into the mixed solution, mix well, seal and store in a constant temperature oven at 70°C Fully swell; continuously extrude and foam the fully swollen compound through a screw extruder at a melting temperature of 160°C and a pressure of 9MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 33%, and the vertical burning is UL94-V0 level. the

Example 6

Mix 100 parts of polyvinyl alcohol 1799, 35 parts of melamine phosphate, 6 parts of montmorillonite and 6 parts of talcum powder in a high-speed mixer to make a composite powder; dissolve 6 parts of boric acid and 6 parts of calcium stearate in 40 Parts of plasticizing foaming agent (water: pentaerythritol = 4: 1) to prepare a mixed solution; add the above-mentioned composite powder to the mixed solution, mix well and store in a sealed oven at 75°C to fully swell; after fully swollen The compound is continuously extruded and foamed by a screw extruder at a melting temperature of 170°C and a pressure of 9.5 MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 34%, and the vertical burning is UL94-V0 level. the

Example 7

Mix 100 parts of polyvinyl alcohol 1799, 35 parts of melamine phosphate, 8 parts of aluminum oxide and 8 parts of zinc oxide in a high-speed mixer to make a composite powder; dissolve 8 parts of boric acid and 8 parts of sodium lauryl sulfate in In 45 parts of plasticizing foaming agent (water: sorbitol=4: 1), be mixed with mixed solution; Add above-mentioned composite powder in mixed solution, after mixing, seal and store in 80 ℃ constant temperature oven and fully swell; Will fully The swollen compound is continuously extruded and foamed by a screw extruder at a melting temperature of 175° C. and a pressure of 10 MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 35%, and the vertical burning is UL94-V0 level. the

Example 8

Mix 100 parts of polyvinyl alcohol 1799, 35 parts of melamine phosphate, 10 parts of magnesium oxide and 10 parts of calcium carbonate in a high-speed mixer to make a composite powder; dissolve 10 parts of boric acid and 10 parts of sodium lauryl sulfate in 45 parts of plasticizing foaming agent (water: glycerol = 5: 1) were prepared into a mixed solution; the above-mentioned composite powder was added into the mixed solution, and after mixing, it was sealed and stored in a constant temperature oven at 80°C to fully swell; The fully swollen compound is continuously extruded and foamed by a screw extruder at a melting temperature of 180°C and a pressure of 10 MPa to obtain a halogen-free flame-retardant polyvinyl alcohol foam material. The limiting oxygen index of the foam material is 36%, and the vertical burning is UL94-V0 level. the

Claims (10)

1. Zero halogen flame resistance polyethylene alcohol foam materials is characterized in that this foam materials is to be got through melt foaming by by weight following component:

And the limiting oxygen index(LOI) of this foam materials is 28～36% by ASTM D2863 standard testing, and vertical combustion is the UL94V0 level by the ASTMD3801 standard testing.

2. Zero halogen flame resistance polyethylene alcohol foam materials according to claim 1 is characterized in that said Z 150PH is the polymerization degree 500～2400, in the alcoholysis degree 88～99% any; Nitrogen-phosphorus halogen-free flame retardants be in melamine phosphate, melamine polyphosphate or the melamine pyrophosphate any; The plasticising whipping agent is any mixture formed by weight 1: 1～5: 1 in water and ethanol, terepthaloyl moietie, USP Kosher, tetramethylolmethane or the sorbyl alcohol.

3. Zero halogen flame resistance polyethylene alcohol foam materials according to claim 1 or claim 2, it is characterized in that said catalyzer be in aluminum oxide, Natural manganese dioxide, phosphomolybdate, aluminosilicate, silicomolybdate, 4A molecular sieve, hydrotalcite or the polynite any; Nucleator be in talcum powder, lime carbonate, silicon-dioxide or the zinc oxide any; Tensio-active agent be in alkyl-sulphate, AS, stearate, siloxanes or the fluorine carbon tensio-active agent any; Linking agent is boric acid or borax.

4. the preparation method of Zero halogen flame resistance polyethylene alcohol foam materials according to claim 1 is characterized in that the process step of this method and condition are following:

(1) earlier 100 parts of Z 150PH, 20～35 parts of nitrogen-phosphorus halogen-free flame retardantss, 0.1～10 part of catalyzer, 0.1～10 portion of nucleator are added in the high-speed mixer mixing and process composite granule; With being mixed with mixing solutions in 0.1～10 part of tensio-active agent and 30～45 parts of plasticising whipping agents of 0.1～10 part of linking agent adding, again composite granule is added in the mixing solutions in 60～80 ℃ of abundant swellings then;

(2) abundant swollen composite granule continuous extrusion foaming under 140～180 ℃ of melt temperatures, pressure 8～10MPa is promptly got Zero halogen flame resistance polyethylene alcohol foam materials.

5. like the preparation method of the said Zero halogen flame resistance polyethylene of claim 4 alcohol foam materials, it is characterized in that the used Z 150PH of this method is the polymerization degree 500～2400, in the alcoholysis degree 88～99% any.

6. like the preparation method of claim 4 or 5 said Zero halogen flame resistance polyethylenes alcohol foam materialss, it is characterized in that the used nitrogen of this method-phosphorus halogen-free flame retardants be in melamine phosphate, melamine polyphosphate or the melamine pyrophosphate any.

7. like the preparation method of claim 4 or 5 said Zero halogen flame resistance polyethylene alcohol foam materialss, it is characterized in that the used plasticising whipping agent of this method is any mixture formed by weight 1: 1～5: 1 in water and ethanol, terepthaloyl moietie, USP Kosher, tetramethylolmethane or the sorbyl alcohol.

8. like the preparation method of claim 4 or 5 said Zero halogen flame resistance polyethylenes alcohol foam materialss, it is characterized in that this method catalyst system therefor be in aluminum oxide, Natural manganese dioxide, phosphomolybdate, aluminosilicate, silicomolybdate, 4A molecular sieve, hydrotalcite or the polynite any; Nucleator be in talcum powder, lime carbonate, silicon-dioxide or the zinc oxide any; Tensio-active agent be in alkyl-sulphate, AS, stearate, siloxanes or the fluorine carbon tensio-active agent any; Linking agent is boric acid or borax.

9. like the preparation method of the said Zero halogen flame resistance polyethylene of claim 6 alcohol foam materials, it is characterized in that this method catalyst system therefor be in aluminum oxide, Natural manganese dioxide, phosphomolybdate, aluminosilicate, silicomolybdate, 4A molecular sieve, hydrotalcite or the polynite any; Nucleator be in talcum powder, lime carbonate, silicon-dioxide or the zinc oxide any; Tensio-active agent be in alkyl-sulphate, AS, stearate, siloxanes or the fluorine carbon tensio-active agent any; Linking agent is boric acid or borax.

10. like the preparation method of the said Zero halogen flame resistance polyethylene of claim 7 alcohol foam materials, it is characterized in that this method catalyst system therefor be in aluminum oxide, Natural manganese dioxide, phosphomolybdate, aluminosilicate, silicomolybdate, 4A molecular sieve, hydrotalcite or the polynite any; Nucleator be in talcum powder, lime carbonate, silicon-dioxide or the zinc oxide any; Tensio-active agent be in alkyl-sulphate, AS, stearate, siloxanes or the fluorine carbon tensio-active agent any; Linking agent is boric acid or borax.

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