KR100485952B1 - Thermosetting inflammable material composition - Google Patents

Abstract

The present invention relates to a thermosetting flame retardant composition for eliminating corrosion and discoloration of a galvanized iron wire sheath and a wire braid of a cable, comprising 100 parts by weight of a mixed base resin of an ethylene vinyl acetate copolymer and an ethylene vinyl acetate- , 0.5 to 5 parts by weight of a lubricant and a processing aid, 2 to 10 parts by weight of an antioxidant, 5 to 20 parts by weight of a flame-retardant auxiliary, 0.5 to 5 parts by weight of a coupling agent 0.5 5 to 5 parts by weight, 0.5 to 5 parts by weight of a crosslinking auxiliary and 3 to 15 parts by weight of a crosslinking agent. Further, the flame retardant material composition according to the present invention is also excellent in low-ductility and flame retardancy when it is burned.

Description

TECHNICAL FIELD The present invention relates to a thermosetting inflammable material composition,

The present invention relates to a thermosetting flame retardant material composition, and more particularly, to a thermosetting flame retardant material composition for use in a zinc-plated steel wire sheath and a wire braiding material, which are produced by acid gas generated during crosslinking by a peroxide of a flame retardant material using ethylene vinyl acetate copolymer as a base resin And a thermosetting halogen-free flame retardant material for eliminating corrosion and discoloration.

The galvanizing plated on the iron wire sheath and the iron wire braid as described above is intended to suppress the corrosion of the iron wire during use. However, discoloration and corrosion are promoted by the acidic gas and moisture generated during the crosslinking process, thereby causing problems in long-term use.

The wire sheath and wire sheath are located outside the cable and act as tensile wires to improve the durability of the cable. Since the wire is basically corrosive, it is plated with various materials to improve its durability so that it can be effectively used during decades of cable use.

However, zinc is highly corrosive and easily corroded under certain conditions. In particular, it may be corroded by normal manufacture or by handling before completion of the finished product. Therefore, many technical efforts and techniques for preventing or suppressing the corrosion of galvanized iron wire sheathing and wire braiding are known.

In the prior art, the crosslinking process was controlled in order to prevent discoloration and corrosion of the galvanized iron wire sheath or the iron wire braid in the crosslinking process. Generally, the thermosetting cable is crosslinked in a short time at a high temperature crosslinking pipe of 160 ~ 210 ° C. In order to remove the crosslinking by-products generated in the crosslinking process, various methods such as removing it naturally while drying at a certain temperature after cross-linking, forcibly introducing a vacuum state, and removing the crosslinked product from the outside are applied.

However, the conventional methods for removing cross-linking by-products are unproductive in terms of time or economics, such as a separate process other than a cross-linking process. In the crosslinking process at a high temperature for a short time, the post-process as described above could be applied. However, in the crosslinking process at a low temperature for a long time, an additional post-process was difficult.

In the prior art, there was also a material approach to overcome the limitations of the process. There have been many efforts to replace resin, which is the main cause of acid gas, during the crosslinking process. Typically, an ethylene-vinyl acetate copolymer, which produces acetic acid, and an ethylene-based copolymer that triggers an acid gas have been replaced by ordinary rubber. However, these simple substitutions with rubber are insufficient to generally satisfy the required properties of materials and cables, such as flame retardancy and oil resistance, and have presented many technical problems in material development.

Recently, environmental concerns and regulations have been strengthened, and halogen-containing resins and halogen compounds, which have been used previously, have been limitedly applied. As a general rubber material containing no halogen, it was difficult to satisfy the flame retardancy grade of IEC 332-3 cat.A class.

Further, halogen-containing rubber and olefin-based flame retardant materials have excellent flame retardancy but are limited in satisfying corrosion and low fuming characteristics that can minimize the effects on life and equipment in the event of a fire. Therefore, in recent years, development of a flame retardant material that satisfies flame retardancy and low fuming characteristics by using an olefin-based material that does not contain halogen is a problem to be solved.

It is an object of the present invention to provide a thermosetting flame retardant composition which suppresses corrosion and discoloration of a wire sheath and a wire braid, has low flammability, flame retardancy and fire stability when burned. .

It is an object of the present invention to provide a process for producing a water-insoluble base resin, which comprises mixing 100 parts by weight of a mixed base resin of an ethylene vinyl acetate copolymer and an ethylene vinyl acetate having a polar group introduced thereinto in the presence of a mixture of magnesium hydroxide and hydrotalcite (magnesium aluminum hydroxide carbonate hydrate) A flame-retardant auxiliary agent, 0.5 to 5 parts by weight of a coupling agent, and 0.5 to 5 parts by weight of a crosslinking auxiliary agent; And 3 to 15 parts by weight of a crosslinking agent.

In the present invention, a halogen-free flame retardant material which satisfies the flame retardancy class of IEC 332-3 cat.A grade which is difficult to satisfy as a general rubber material containing no halogen compound and satisfies electric characteristics has been developed. In addition, halogen-free olefin-based flame-retardant materials were developed to satisfy the low fuming characteristics of IEC 601034.

In the present invention, a flame retardant material suitable for a long-time crosslinking process at a low temperature of about 100 to 130 ° C, based on the decomposition temperature of the peroxide, is used as a flame retardant, And the corrosion of the galvanized iron wire sheath and the iron wire braid by iron wire were fundamentally solved.

In the present invention, an ethylene vinyl acetate copolymer which generates acetic acid and other acid gases during the crosslinking process is applied as a base resin. The degree of acetic acid and acid gas production in the crosslinking process depends on the vinyl acetate content of the ethylene vinyl acetate copolymer. In addition, since acetic acid generated in the combustion process contributes to improvement of flame retardancy, the application range of vinyl acetate is appropriately controlled in the present invention.

It is also important to control the amount of acid gas generated to prevent and inhibit corrosion and discoloration of the galvanized iron wire sheath and wire braid, as well as to neutralize or capture the generated acid gas. Therefore, in the present invention, magnesium hydroxide and hydrotalcite (magnesium aluminum hydroxide carbonate hydrate) were mixedly used as a neutralizing agent or trapping agent for acid gas.

Magnesium hydroxide is generally used as a flame retardant according to a heat absorbing mechanism, and its pea (hydrogen ion concentration) is basic and can exert both its role as a flame retardant and a neutralizer. However, since magnesium hydroxide alone did not have an effect of suppressing corrosion, hydrotalcite, which is a basic metal hydroxide of a different kind, was added. In addition, since the magnesium hydroxide alone contained a hydroxide, it was possible to improve the limit of the flame retardancy.

In the present invention, polycarbodiimide which is an effective antioxidant for improving resistance to hydrolysis in water and acidic atmosphere and crosslinking at high temperature is applied.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description of the invention and the preferred embodiments thereof.

Hereinafter, the composition of the thermosetting flame retardant composition according to the present invention will be described.

The flame retardant material composition according to the present invention comprises 80 to 180 parts by weight of a mixed metal hydride compound of a different kind per 100 parts by weight of a mixed resin of ethylene vinyl acetate copolymer and ethylene vinyl acetate into which a polar group is introduced as a base resin, 2 to 10 parts by weight of an antioxidant, 5 to 20 parts by weight of a flame retardant auxiliary, 0.5 to 5 parts by weight of a coupling agent, 0.5 to 5 parts by weight of a crosslinking aid and 3 to 15 parts by weight of a crosslinking agent.

The base resin used as the main flame retardant material is a mixture of two or three different resins having the same or different physical properties and chemical structures. Among 100 parts by weight of the two or three kinds of mixed base resins, ethylene vinyl acetate has a vinyl acetate content of 28 to 70 wt%.

When the content of vinyl acetate in the entire base resin was 33 wt% or less, the oil resistance was lowered and the elongation percentage was decreased. In addition, when the content of vinyl acetate was 45 wt% or more, the mechanical properties such as tensile strength and elongation were remarkably lowered, so that the content of vinyl acetate was mixed with 28 wt%, which is low.

Ethylene vinyl acetate with a polar group was effective in improving mechanical and thermal properties. An ethylene vinyl acetate trimer having a polar group introduced with a polar group content of 0.5 to 2.0 wt% and a vinyl acetate content of 14 to 28 wt% was used. 0 to 15 parts by weight of ethylene vinyl acetate to which a polar group has been introduced is applied to 100 parts by weight of a base resin mixed with two or three kinds of paper.

80 to 180 parts by weight of two types of magnesium hydroxide and hydrotalcite are mixed with 100 parts by weight of the base resin. When the amount of the hydrated metal compound is less than 80 parts by weight, the flame retardancy can not be secured. When the amount is more than 180 parts by weight, workability and elongation percentage are lowered. In order to solve the corrosion problem of the galvanized iron wire by the flame retardant material according to the present invention and to satisfy the mechanical characteristic, the flame retardant characteristic and the low fuming characteristic, the hydrated metal compound is not treated with the surface, or magnesium hydroxide surface- Respectively.

In the present invention, 70 to 140 parts by weight of magnesium hydroxide is used. When the amount is less than 70 parts by weight, the effect of inhibiting corrosion by mixing with hydrotalcite can not be obtained. Further, a synergistic effect on flame retardancy and low fuming characteristics could not be obtained. When the amount is more than 140 parts by weight, the effect of increasing the flame retardancy due to a large amount of magnesium hydroxide was not large, and the tensile strength and elongation were decreased.

Hydrotalcite was used in an amount of 10 to 40 parts by weight for the purpose of inhibiting corrosion and improving flame retardancy by mixing with magnesium hydroxide. In the case of 10 parts by weight or less, corrosion inhibition effect due to the synergistic action with the mixed magnesium hydroxide could not be expected and it did not contribute to improvement of the flame retardancy. When the amount is more than 40 parts by weight, a large amount of hydrotalcite inhibiting effect by corrosion is not great, and the tensile strength and elongation rate are rapidly deteriorated.

Among the antioxidants, 1 to 8 parts by weight of polycarbodiimide which improves resistance to hydrolysis in water and acidic atmosphere and crosslinking at high temperature was used. When the amount is less than 1 part by weight, the effect of suppressing corrosion due to the synergistic effect with the metal hydroxide is not significant. When the amount is more than 8 parts by weight, the mechanical properties are deteriorated.

0.1 to 5 parts by weight of a lubricant and a processing aid are used. When the amount of the lubricant was less than 0.5 part by weight, improvement in workability due to a decrease in viscosity of the material could not be expected. When the amount of the lubricant was more than 5 parts by weight, the flame retardancy,

0.5 to 5 parts by weight of a coupling agent was used. As the coupling agent, vinyltrimethoxyethoxysilane and oligomeric vinyltrimethoxysilane or vinyltriethoxysilane were used. When the amount is less than 0.5 part by weight, the improvement of the tensile strength can not be expected. When the amount is more than 5 parts by weight, the tensile strength is not increased and the elongation and flame retardancy are decreased.

0.5 to 5 parts by weight of a crosslinking auxiliary was used. As the crosslinking auxiliary, triaryl cyanurate and triaryl isocyanurate were used. When the content of the crosslinking aid is 0.5 parts by weight or less, the oil resistance, the tensile strength and the flame retardancy are lowered, and the elongation percentage is rapidly lowered when the amount is 5 parts by weight or more.

3 to 15 parts by weight of a crosslinking agent was used. 1,1-Bistabutylperoxy-3,3,5-trimethylcyclohexane was used as the crosslinking agent. When the content of the crosslinking agent is less than 3 parts by weight, the tensile strength and the flame retardancy are not satisfied. When the amount is more than 15 parts by weight, the elongation percentage is decreased.

In the present invention, a flame retardant material which does not affect the corrosion of the zinc wire and the fire stability is secured through the proper selection and mixing of the resin into which the polar group is introduced, the hydroxyl compound and the antioxidant.

Hereinafter, embodiments and actions of the thermosetting flame retardant composition according to the present invention will be described.

Table 1 shows the compounding ratios according to each example, and Table 2 shows the physical property evaluation results of each example.

The mixing ratio Compounding agent Example Comparative example One 2 3 4 One 2 3 Ethylene vinyl acetate copolymer 100 100 100 100 100 100 60 Ethylene propylene trimer 40 Antioxidant 2 2 6 6 2 2 2 Lubricant 1.5 1.5 1.5 1.5 1.5 1.5 3 Magnesium hydroxide 150 120 150 120 170 Aluminum hydroxide 170 Hydrotalcite 30 30 Crosslinking auxiliary 2 2 2 2 2 2 2 Cross-linking agent 9 9 9 9 9 9 9

Results of physical property evaluation Evaluation items Example Comparative Example One 2 3 4 One 2 3 Corrosive ¹⁾ medium Prize Prize Prize Ha Ha Ha Flexibility ²⁾ Transmittance (%) 85 90 83 87 65 68 57 Flammability ³⁾ Burning length (m) 1.8 1.52 1.83 1.46 2.12 2.6 2.46 Tensile strength ⁴⁾ kgf / mm ² 1.28 1.31 1.24 1.23 0.92 1.12 0.67 Elongation rate ⁴⁾ % 181 166 178 156 287 154 320 Oxygen index ⁵⁾ % 34 35 34 35.5 38 32 29

1) Corrosion: Judge the degree of corrosion of steel wire after finishing (the degree of discoloration is divided into three stages: phase-discolorationless, medium-gray to slightly discolored,

2) Flexibility: The cable was tested in accordance with IEC 1034. The transmittance should be more than 60%.

3) Flame retardancy: It was tested according to the flame retardant test standard of IEC 332-3 cat.A. 70,000 Btu / hr of heat is applied for 40 minutes. The burning length of the cable after combustion test shall be 2.44m.

4) Tensile strength and elongation: Tensile strength and elongation were measured according to ASTM D 638.

5) Oxygen Index: The test was conducted according to ASTM D 2863.

In Examples 1 and 2, an ethylene vinyl acetate copolymer and an ethylene vinyl acetate trimer having a polar group introduced therein were mixed and used as a base resin. The effects of magnesium hydroxide and hydrotalcite on the corrosion resistance, flame retardancy, low ductility and mechanical properties of galvanized iron wires were investigated. Particularly, the magnesium hydroxide used in the present invention is not surface-treated or surface-treated with silane and polymer. Then, a cross-linking agent and a cross-linking agent for cross-linking with a lubricant and an antioxidant were applied.

In Examples 3 to 4, the effect of the antioxidant, magnesium hydroxide, and hydrotalcite mixed in the present invention is shown. Then, flame retardants and additives as in Examples 1 to 4 were applied.

In the case of Comparative Examples 1 to 3, the test results for the case where a flame retardant such as magnesium hydroxide or aluminum hydroxide surface-treated with stearic acid or oleic acid was applied to the resin of the ethylene vinyl acetate copolymer alone was compared . Also, in order to minimize the production of acid gas during the crosslinking process, the ethylene vinyl acetate copolymer and the ethylene propylene trimer were also mixed.

The flame retardant materials mentioned in the above examples were molded in an open roll after mixing at 170 DEG C for 10 minutes, and then test specimens were prepared and evaluated for their properties. IEC 332-3 cat.A flame retardant test and IEC 601034 smoke density test were carried out.

Test results of Examples 1 to 4 show that the degree of corrosion of galvanized iron wire after crosslinking is improved when mixed with hydrotalcite, rather than when magnesium hydroxide alone is added. In addition, corrosion of the iron wire can be solved by using an appropriate combination of a basic flame retardant such as magnesium hydroxide and hydrotalcite and an antioxidant of polycarbodiimides. Hydrotalcite has a synergistic effect with mixed use of magnesium hydroxide and has improved flame retardancy and low ductility.

As a result of the flame retardancy test for the cable using the same material as the embodiment of the present invention, the combustion length showed a combustion characteristic of less than 1.2 m and the result of the low flammability test showed a transmittance of 70% or more.

Magnesium hydroxide surface-treated with stearic acid or oleic acid or various aluminum hydroxide as in the comparative example could not improve the corrosion of galvanized iron wire. The flame retardancy and the general mechanical properties of the material with ethylene propylene trimer were lowered.

The above-mentioned thermosetting flame retardant composition according to the present invention has excellent effects in suppressing corrosion and discoloration of wire sheathing and wire braiding of cables, excellent low ductility and flame retardancy in burning, and excellent fire stability .

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. Accordingly, the appended claims are intended to cover such modifications and changes as fall within the scope of the invention.

Claims (7)

80 to 180 parts by weight of a hydrated metal compound in which magnesium hydroxide and hydrotalcite are mixed with 100 parts by weight of a mixed base resin of an ethylene vinyl acetate copolymer and ethylene vinyl acetate to which a polar group has been introduced, 0.5 to 5 parts by weight of a lubricant and a processing aid , 2 to 10 parts by weight of an antioxidant, 5 to 20 parts by weight of a flame retardant auxiliary, 0.5 to 5 parts by weight of a coupling agent, 0.5 to 5 parts by weight of a crosslinking auxiliary and 3 to 15 parts by weight of a crosslinking agent. The thermosetting flame retardant material composition according to claim 1, wherein the vinyl acetate content of the ethylene vinyl acetate copolymer is 28 to 70 wt%. The thermosetting flame retardant material composition according to claim 1, wherein the polar group-introduced ethylene vinyl acetate has a polar group content of 0.5 to 2.0 wt% and an ethylene vinyl acetate content of 14 to 28 wt%. The thermosetting flame retardant material composition according to claim 1, wherein the etherified vinyl acetate into which the polar group is introduced is composed of 0 to 15 parts by weight based on 100 parts by weight of the base resin. The thermosetting flame retardant material composition according to claim 1, wherein the hydrated metal compound comprises 70 to 140 parts by weight of magnesium hydroxide and 10 to 40 parts by weight of hydrotalcite. The thermosetting flame retardant material composition according to claim 1 or 5, wherein the magnesium hydroxide is non-surface-treated or surface-treated with silane or polymer. The thermosetting flame retardant material composition according to claim 1, wherein the antioxidant is 1 to 8 parts by weight of a polycarbodiimide.