JPH0625476A - Flame-retardant polyolefin resin composition - Google Patents

Abstract

PURPOSE:To provide a polyolefin resin compsn. which has been made flame- retardant without detriment to its characteristics, i.e., low density and high strengths, and without increasing the amt. of a corrosive gas or smoke generated during burning. CONSTITUTION:This compsn. is prepd. by compounding 100 pts.wt. polyolefin with 1-20 pts.wt. red phosphorus and 1-30 pts.wt thermally expandable graphite which expands at least 100-fold in the direction of C axis when rapidly heated (80-1,000 deg.C) and contains 80-mesh-on particles in an amt. of at least 80%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polyolefin resin composition which has excellent flame-retardant performance and does not generate corrosive gas during combustion.

[0002]

2. Description of the Related Art A great deal of plastic materials are required to be flame-retardant, such as insulating materials for electric wires and cables, enclosures for electric and electronic equipment, materials for railway vehicles, automobiles, and construction materials. Flame retardant performance is also increasing. As a technique for imparting flame retardancy to these plastic materials, conventionally, a method of mainly incorporating a halogen-based flame retardant has been dealt with. Further, as another method, a method of blending a hydrated metal compound such as magnesium hydroxide or aluminum hydroxide is known.

However, the one containing a halogen-based flame retardant has a problem that a large amount of smoke is generated during combustion and the generation of corrosive gas such as hydrogen halide. That is, the resin composition containing a halogen-based flame retardant, damage to the equipment and devices due to the corrosive gas generated during combustion,
People who evacuate in the event of a fire may lose their way out due to smoke. Hydrated metal compounds such as magnesium hydroxide and aluminum hydroxide suppress smoke generation as described above and do not generate corrosive gas by themselves, so in recent years, they have also been used as substitutes for halogen-based flame retardants. It is increasing. However, these hydrated metal compounds require a large amount of blending in order to impart sufficient flame retardancy, so that the mechanical properties of the resin composition are significantly reduced and the specific gravity of the resin composition is increased. However, one of the features of polymer materials is that they are light and strong, but hydrated metal compounds greatly impair these features, and it cannot be said that they are a sufficiently satisfactory flame retardant method. Met.

[0004]

Therefore, attempts have recently been made to blend red phosphorus, but since the flame retardancy obtained by blending red phosphorus alone is insufficient, red phosphorus and hydrated metal Attempts have been made to blend them together with the compounds, or to blend red phosphorus and hydrated metal compounds with heat-expandable graphite for the purpose of imparting flame retardancy. However, in the conventional technology, the addition of a hydrated metal compound is indispensable for flame retardation by a non-halogen system, and it is inevitable that the mechanical properties of the resin composition are deteriorated and the specific gravity of the resin composition is increased. Is.

[0005]

[Means for Solving the Problems] Under these circumstances, the present inventors have found that in a polyolefin resin composition,
It has been found that a mixture of heat-expandable graphite having a specific expandability and a specific particle shape, and red phosphorus or a phosphorus compound exerts a remarkable flame retardant effect, and is described in the above claims. The present invention has been achieved.

The polyolefin resin used in the present invention includes olefin monomers such as low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, polybutene-1, polyisobutylene, and poly-4-methyl-1-pentene. Homopolymers, ethylene-acrylic acid, ethylene-ethyl acrylate, ethylene-methyl acrylate, ethylene-acrylamide, ethylene-methacrylic acid, ethylene-methyl methacrylate, ethylene-glycidyl methacrylate, ethylene-maleic anhydride, And ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene-
Examples thereof include a diene compound copolymer, a copolymer containing an olefin monomer such as an ionomer resin, or a mixture of two or more kinds thereof.

The red phosphorus used in the present invention is 20 μm in view of the dispersibility in the resin and the influence on the mechanical properties of the resin composition.
Those having a particle size of m or less are preferable. Further, red phosphorus surface-treated with a phenol resin, a titanate coupling agent or the like can also be used. If the content of the red phosphorus is less than 1 part by weight with respect to 100 parts by weight of the polyolefin resin, the flame retarding effect is insufficient, and if it exceeds 20 parts by weight, the mechanical properties of the resin composition are significantly impaired. The content of the red phosphorus is 100 parts by weight of the polyolefin resin,
It is necessary to mix 1 to 20 parts by weight.

The phosphorus compounds used in the present invention are exemplified below, but the phosphoric acid referred to here includes all of phosphoric acid, phosphorous acid and hypophosphorous acid. Examples of the phosphorus compound used in the present invention include triphenyl phosphate, octyl diphenyl phosphate, trioctyl phosphate, tricresyl phosphate, phosphate esters such as dibutyl hydrogen phosphate, sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate, Metal salts of phosphoric acid such as zinc phosphate and aluminum phosphate, and hydrates of these metal salts, ammonium phosphate, ammonium polyphosphate, ethylenediamine phosphate, salts of phosphoric acid such as diethylenetriamine phosphate with ammonia or amines, and Examples thereof include condensates thereof, guanidine phosphates, phosphines and phosphine oxides, melamine-modified ammonium polyphosphate, and mixtures of two or more of these phosphorus compounds. In the case of phosphoric acid esters, salts of phosphoric acid with ammonia or amines, and condensates thereof, the amount of the phosphorus compound is preferably 1 to 30 parts by weight based on 100 parts by weight of the polyolefin resin.
This is because if it is less than 1 part by weight, the flame retarding effect is insufficient, and if it exceeds 30 parts by weight, the hygroscopicity of the resin composition becomes high. When the phosphorus compound is a metal salt of phosphoric acid and / or a hydrate of these metal salts, it is preferable to add 1 to 150 parts by weight to 100 parts by weight of the polyolefin resin. 1
This is because if it is less than 150 parts by weight, the flame retarding effect is insufficient, and if it exceeds 150 parts by weight, the mechanical properties of the resin composition are significantly impaired. Further, among the phosphorus compounds, those having a melting point equal to or higher than the resin kneading temperature are preferably those having a particle diameter of 2 μm or less in view of dispersibility in the resin and influence on the mechanical properties of the resin composition. Further, it is preferable to use those surface-treated with a silane coupling agent, a titanate coupling agent, a fatty acid or the like.

The heat-expandable graphite used in the present invention has 100 times or more expandability in the C-axis direction (direction perpendicular to the cleavage plane of graphite) when rapidly heated (800 to 1000 ° C.). is necessary. This is because those that do not have 100 times or more expandability have much less flame retardancy than those that have 100 times or more expandability. The expansivity referred to in the present invention means the difference between the specific volume after heating (ml / g) and the specific volume at room temperature. A method for measuring the expansivity will be specifically described. Put 2g of heat-expandable graphite into a quartz beaker preheated to 1000 ° C in an electric furnace and quickly
A quartz beaker is placed in an electric furnace heated to 00 ° C. for 10 seconds, then taken out of the furnace and allowed to cool to room temperature. After that, 100 ml of the expanded graphite was weighed and the loose apparent specific gravity (g / ml) was measured, and the specific volume was set to 1 / the loose apparent specific gravity. Next, the specific volume of the heat-expandable graphite at room temperature which was not heated was determined by the same method, and the expansibility = specific volume after heating−specific volume at room temperature. When observing the heat-expandable graphite before and after expansion with an electron microscope, almost no expansion was observed in the A-axis direction and the B-axis direction, and expansion was observed only in the C-axis direction. The difference from the specific volume at room temperature was defined as the expansibility in the C-axis direction. 80% of particle size is 80 mesh on due to classification
It is necessary to be above, and preferably 80% or more and 99% or less. 80% on 80 mesh
If it is less than 100%, the flame retardancy is insufficient, and if it exceeds 99%, the shape retention performance of the resin composition when exposed to a flame tends to be slightly deteriorated, which is not preferable. Preferable examples of the heat-expandable graphite include scaly graphite that has been subjected to an oxidation treatment. As a preferable example of the oxidation treatment,
There are electrolytic oxidation in sulfuric acid, oxidation treatment of mixed acid of phosphoric acid and nitric acid, sulfuric acid and nitric acid, perchloric acid, and the like. The blending amount of the heat-expandable graphite needs to be 1 to 30 parts by weight with respect to 100 parts by weight of the polyolefin. This is because if it is less than 1 part by weight, the flame retarding effect is insufficient, and if it exceeds 30 parts by weight, the mechanical properties of the resin composition are significantly impaired.

Other flame retardants can be used in combination with the resin composition of the present invention within a range that does not impair the effects of the present invention. Further, if necessary, various additives such as an inorganic filler, a colorant, an antioxidant and the like can be blended.

[0011]

EXAMPLES The effects of the present invention will be clarified below with reference to specific examples, but the present invention is not limited to these examples.

Examples 1 to 7 100 parts by weight of an ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation: Ultracene 630) and red phosphorus (manufactured by Phosphorus Chemical Co., Ltd .: Novarred 120UF) and thermally expanded. Graphite (Chuo Kasei Co., Ltd .: 80 mesh on 96%, 10
The flame retardant resin composition was prepared by using an extruder by adding the amount of expansion at 210 ° C. 210 times) in the amounts shown in Table 1. The obtained resin composition was injection molded to prepare a test piece. Mechanical properties were evaluated by tensile fracture strength and elongation according to JIS K 7113 test method. Further, the combustion test was evaluated by an oxygen index based on JIS K 7201 test method and UL-94 combustion test. The results are shown in Table 1.

Examples 8 and 9 Ethylene-vinyl acetate copolymer 100 used in Example 1
Triphenyl phosphate (TPP manufactured by Akzo Japan Co., Ltd.) and the heat-expandable graphite used in Example 1 were mixed in the respective parts by weight in the amounts shown in Table 2, and the flame-retardant resin composition was extruded by an extruder. Was prepared. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Examples 10 and 11 Ethylene-vinyl acetate copolymer 100 used in Example 1
In parts by weight, ammonium polyphosphate (Rin Kagaku Kogyo Co., Ltd.)
Manufactured: PA-6) and the heat-expandable graphite used in Example 1 were mixed in the amounts shown in Table 2, and a flame-retardant resin composition was prepared by an extruder. The flame retardancy of the obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Examples 12 and 13 Ethylene-vinyl acetate copolymer 100 used in Example 1
In parts by weight, guanidine phosphate (manufactured by Sanwa Chemical Co., Ltd .:
Appinone-301) and the heat-expandable graphite used in Example 1 were mixed in the amounts shown in Table 2, and a flame-retardant resin composition was prepared by an extruder. The flame retardancy of the obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1 The ethylene-vinyl acetate copolymer used in Example 1 was evaluated for mechanical properties and flame retardancy in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 2 Ethylene-vinyl acetate copolymer 100 used in Example 1
A resin composition was prepared by blending 15 parts by weight of red phosphorus. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 3 Ethylene-vinyl acetate copolymer 100 used in Example 1
A resin composition was prepared by blending 15 parts by weight of heat-expandable graphite. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 4 As the heat-expandable graphite, 80 mesh-on content 70
%, Expandability at 1000 ° C 180 times (Chuo Kasei Co., Ltd.)
The mechanical properties and flame retardancy were evaluated in the same manner as in Example 4 except that the product manufactured by M. Co., Ltd. was used. The results are shown in Table 3.

Comparative Example 5 As the heat-expandable graphite, the content of 80 mesh on 97
%, Expandability at 1000 ° C 70 times (Chuo Kasei Co., Ltd.)
Mechanical properties and flame retardancy were evaluated in the same manner as in Example 4 except that was used. The results are shown in Table 3.

Comparative Example 6 Ethylene-vinyl acetate copolymer 100 used in Example 1
25 parts by weight of red phosphorus used in Example 1 and 10 parts by weight of heat-expandable graphite were mixed with the parts by weight to prepare a resin composition. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 7 Ethylene-vinyl acetate copolymer 100 used in Example 1
5 parts by weight of red phosphorus used in Example 1 and 35 parts by weight of heat-expandable graphite were mixed with the parts by weight to prepare a resin composition.
The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 8 Ethylene-vinyl acetate copolymer 100 used in Example 1
100 parts by weight of magnesium hydroxide (manufactured by Kyowa Chemical Industry Co., Ltd .: Kisuma 5A) and 10 parts by weight of red phosphorus used in Example 1 were blended with parts by weight to prepare a resin composition.
The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 3. Comparative Example 9 Ethylene-vinyl acetate copolymer 100 used in Example 1
1 part by weight of magnesium hydroxide used in Comparative Example 8
00 parts by weight and 15 parts by weight of the heat-expandable graphite used in Example 1 were blended to prepare a resin composition. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 10 Ethylene-vinyl acetate copolymer 100 used in Example 1
A resin composition was prepared by mixing 10 parts by weight of triphenyl phosphate used in Example 8 with parts by weight. The flame retardancy of the obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 4.

Comparative Example 11 Ethylene-vinyl acetate copolymer 100 used in Example 1
20 parts by weight of ammonium polyphosphate used in Example 10 was blended with parts by weight to prepare a resin composition. The flame retardancy of the obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 4.

Comparative Example 12 Ethylene-vinyl acetate copolymer 100 used in Example 1
Guanidine phosphate 2 used in Example 12 based on parts by weight
0 part by weight was compounded to prepare a resin composition. The flame retardancy of the obtained resin composition was evaluated in the same manner as in Example 1.
The results are shown in Table 4.

Comparative Example 13 As the heat-expandable graphite, 80 mesh-on content 70
%, Expandability at 1000 ° C 180 times (Chuo Kasei Co., Ltd.)
A resin composition was prepared and flame retardancy was evaluated in the same manner as in Example 9 except for using The results are shown in Table 4.

Comparative Example 14 As the heat-expandable graphite, the content of 80 mesh on was 97
%, Expandability at 1000 ° C 70 times (Chuo Kasei Co., Ltd.)
A resin composition was prepared and flame retardancy was evaluated in the same manner as in Example 9 except that was used. The results are shown in Table 4.

Comparative Example 15 80 mesh-on content 70 as the heat-expandable graphite
%, Expandability at 1000 ° C 180 times (Chuo Kasei Co., Ltd.)
A resin composition was prepared and flame retardancy was evaluated in the same manner as in Example 11 except that (Production) was used. The results are shown in Table 4.

Comparative Example 16 As the heat-expandable graphite, 80 mesh-on content rate 97
%, Expandability at 1000 ° C 70 times (Chuo Kasei Co., Ltd.)
A resin composition was prepared and flame retardancy was evaluated in the same manner as in Example 11 except that was used. The results are shown in Table 4.

Comparative Example 17 As the heat-expandable graphite, 80 mesh-on content 70
%, Expandability at 1000 ° C 180 times (Chuo Kasei Co., Ltd.)
A resin composition was prepared and flame retardancy was evaluated in the same manner as in Example 12 except that the resin composition was used. The results are shown in Table 4.

Comparative Example 18 As the heat-expandable graphite, the content of 80 mesh on was 97
%, Expandability at 1000 ° C 70 times (Chuo Kasei Co., Ltd.)
A resin composition was prepared and flame retardancy was evaluated in the same manner as in Example 12 except that was used. The results are shown in Table 4.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

As shown in Tables 1 and 2, the flame-retardant EVA composition of the present invention showed extremely excellent flame retardancy in the UL-94 combustion test and, in addition, the EVA of Comparative Example 1 in Table 3. It can be seen that the increase in specific gravity is small and the physical properties of EVA are not so deteriorated.

On the other hand, as shown in Comparative Examples 2 and 3 of Table 3,
It can be seen that sufficient flame retardancy cannot be obtained in the UL-94 combustion test when the same amounts of red phosphorus and heat-expandable graphite are used alone. Further, Comparative Examples 4 and 5 show the results of using the heat-expandable graphite having an 80-mesh-on content of less than 80% and the heat-expandable graphite having an expandability of less than 100 times. It can be seen that burning is not achieved. In addition, Comparative Examples 6 and 7 show the results of mixing red phosphorus and heat-expandable graphite in an amount exceeding the range of the present invention, and it is understood that the elongation is markedly reduced in all cases. Comparative Examples 8 and 9 show the test results of the resin compositions using magnesium hydroxide, but although sufficient flame retardancy was achieved, the increase in specific gravity was large and the decrease in elongation was also evaluated to show the characteristics of EVA. It turns out that it is a big loss. In addition, Comparative Example 10 in Table 4
As shown in ~ 12, the phosphorus compounds used alone are
Sufficient flame retardancy was not obtained, and further, Comparative Examples 13 to
No. 18 shows the results of using heat-expandable graphite having an 80 mesh-on content of less than 80% and heat-expandable graphite having an expandability of less than 100 times, but none of them shows sufficient flame retardancy. I understand.

Examples 14 to 20 Low density polyethylene (manufactured by Tosoh Corporation: Petrosene 20)
3) 100 parts by weight of red phosphorus used in Example 1 and heat-expandable graphite were mixed in the amounts shown in Table 5, and a flame-retardant resin composition was prepared by an extruder. The obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 5.
Shown in.

Examples 21 to 26 The low density polyethylene used in Example 14 was used as the polyolefin, the phosphorus compound used in Examples 8 to 13 and the heat-expandable graphite were blended in the amounts shown in Table 6, and the extruder was used. To prepare a flame-retardant resin composition. The flame retardancy of the obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 6.

Comparative Example 19 The mechanical properties and flame retardancy of the low density polyethylene used in Example 14 were evaluated in the same manner as in Example 1. The results are shown in Table 7.
Shown in.

Comparative Example 20 100 parts by weight of the low density polyethylene used in Example 14,
A resin composition was prepared by mixing 15 parts by weight of red phosphorus. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 7.

Comparative Example 21 100 parts by weight of the low-density polyethylene used in Example 14,
A resin composition was prepared by mixing 15 parts by weight of heat-expandable graphite. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 7.

Comparative Example 22 80 mesh-on content 70 as the heat-expandable graphite
%, Expandability at 1000 ° C 180 times (Chuo Kasei Co., Ltd.)
The mechanical properties and flame retardancy were evaluated in the same manner as in Example 17, except that the product manufactured by Mitsui Chemical Co., Ltd. was used. The results are shown in Table 7.

Comparative Example 23 As the heat-expandable graphite, the content of 80 mesh on was 97
%, Expandability at 1000 ° C 70 times (Chuo Kasei Co., Ltd.)
The mechanical properties and flame retardancy were evaluated in the same manner as in Example 17 except that was used. The results are shown in Table 7.

Comparative Example 24 To 100 parts by weight of the low-density polyethylene used in Example 14, 25 parts by weight of red phosphorus used in Example 1 and 10 parts by weight of heat-expandable graphite were blended to prepare a resin composition. . The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 7.

Comparative Example 25 To 100 parts by weight of the low-density polyethylene used in Example 14, 5 parts by weight of red phosphorus used in Example 1 and 35 parts by weight of heat-expandable graphite were blended to prepare a resin composition. . The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 7.

Comparative Example 26 100 parts by weight of the low-density polyethylene used in Example 14 was mixed with 100 parts by weight of magnesium hydroxide used in Comparative Example 8 and 10 parts by weight of red phosphorus used in Example 1, A resin composition was prepared. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 7.
Shown in.

Comparative Example 27 100 parts by weight of the low-density polyethylene used in Example 14 was mixed with 100 parts by weight of the magnesium hydroxide used in Comparative Example 8 and 15 parts by weight of the heat-expandable graphite used in Example 1. Then, a resin composition was prepared. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1.
The results are shown in Table 7.

Comparative Examples 28 to 36 The low-density polyethylene used in Example 14 was used as the polyolefin, and the phosphorus compound and the heat-expandable graphite were blended alone, or the phosphorus compound and the heat-expandability with a low 80 mesh-on content were used. Blended with graphite, phosphorus compound and 1000 ℃
The flame retardancy of the resin composition containing the heat-expandable graphite having low expandability was evaluated. The results are shown in Table 8.

[0051]

[Table 5]

[0052]

[Table 6]

[0053]

[Table 7]

[0054]

[Table 8]

As shown in Tables 5 and 6, it can be seen that the flame retardant LDPE composition of the present invention has a small increase in specific gravity and exhibits extremely excellent flame retardancy, as in the case of EVA. .

As shown in the results of Tables 7 and 8, it is impossible to obtain a resin composition satisfying both flame retardancy and low specific gravity unless the resin composition of the present invention is used. I see that it is possible.

Examples 27 to 33 Polypropylene (manufactured by Tosoh Corporation: J7030B) 10
The red phosphorus used in Example 1 and the heat-expandable graphite used in Example 1 were each mixed in an amount of 0 part by weight as shown in Table 9, and a flame-retardant resin composition was prepared by an extruder. The obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 9.

Examples 34 to 39 The polypropylene used in Example 27 was used as the polyolefin, the phosphorus compound used in Examples 8 to 13 and the heat-expandable graphite were mixed in the amounts shown in Table 10, and the mixture was hardened by an extruder. A flammable resin composition was prepared. The flame retardancy of the obtained resin composition was evaluated in the same manner as in Example 1. The results are shown in Table 1.
It shows in 0.

Comparative Example 37 The mechanical properties and flame retardancy of the polypropylene used in Example 27 were evaluated in the same manner as in Example 1. The results are shown in Table 11.

Comparative Example 38 100 parts by weight of the polypropylene used in Example 27 and 21 parts by weight of red phosphorus were mixed to prepare a resin composition. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 11.

Comparative Example 39 A resin composition was prepared by mixing 100 parts by weight of the polypropylene used in Example 27 and 21 parts by weight of heat-expandable graphite. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 11.

Comparative Example 40 As the heat-expandable graphite, 80 mesh-on content 70
%, Expandability at 1000 ° C 180 times (Chuo Kasei Co., Ltd.)
The mechanical properties and flame retardancy were evaluated in the same manner as in Example 31 except that the product (made by Japan) was used. The results are shown in Table 11.

Comparative Example 41 As the heat-expandable graphite, the content of 80 mesh on was 97
%, Expandability at 1000 ° C 70 times (Chuo Kasei Co., Ltd.)
The mechanical properties and flame retardancy were evaluated in the same manner as in Example 31 except that was used. The results are shown in Table 11.

Comparative Example 42 To 100 parts by weight of polypropylene used in Example 27, 25 parts by weight of red phosphorus used in Example 1 and 10 parts by weight of heat-expandable graphite were blended to prepare a resin composition. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 11.

Comparative Example 43 5 parts by weight of red phosphorus used in Example 1 and 3 parts of heat-expandable graphite were used with respect to 100 parts by weight of polypropylene used in Example 27.
A resin composition was prepared by mixing 5 parts by weight. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 11.

Comparative Example 44 To 100 parts by weight of polypropylene used in Example 27, 100 parts by weight of magnesium hydroxide used in Comparative Example 8 and 10 parts by weight of red phosphorus used in Example 1 were blended to obtain a resin composition. The thing was prepared. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 11
Shown in.

Comparative Example 45 100 parts by weight of the polypropylene used in Example 27 and 100 parts by weight of the magnesium hydroxide used in Comparative Example 8 and 15 parts by weight of the heat-expandable graphite used in Example 1 were blended. A resin composition was prepared. The mechanical properties and flame retardancy of the obtained resin composition were evaluated in the same manner as in Example 1. The results are shown in Table 11.

Comparative Examples 46 to 54 The polypropylene used in Example 27 was used as the polyolefin, and the phosphorus compound and the heat-expandable graphite were blended alone, or the phosphorus compound and the 80 mesh-on content were less than 80%. The flame retardancy of the resin composition containing the expandable graphite and the resin composition containing the phosphorus compound and the heat-expandable graphite having an expandability less than 100 times was evaluated. The results are shown in Table 12.

[0069]

[Table 9]

[0070]

[Table 10]

[0071]

[Table 11]

[0072]

[Table 12]

As shown in Tables 9 and 10, the flame-retardant PP resin composition of the present invention has a small increase in specific gravity and exhibits extremely excellent flame retardancy as in the case of EVA. I understand. Further, as shown in the results of Tables 11 and 12, it is impossible to obtain a resin composition satisfying both flame retardancy and low specific gravity unless the resin composition of the present invention is used. I understand.

[0074]

As described above, the flame-retardant resin composition of the present invention exhibits excellent flame-retardant properties while maintaining mechanical properties, and is light in weight. Furthermore, since it does not contain halogen, it does not corrode during combustion. There is no generation of volatile gas, the amount of smoke generated during combustion is suppressed,
It is extremely safe.

Front page continuation (72) Inventor Yuji Suzuki, 471 Kawashima-cho, Hodogaya-ku, Yokohama-shi, Kanagawa 2 (72) Inventor Shunichi Endo 1063 91, Ina-cho, Ina-cho, Tsukuba-gun, Ibaraki Prefecture (72) Gen-ichiro Ochiai Tokyo 3-41-8 Kohoku, Adachi-ku, Tokyo

Claims (2)

[Claims] 1. 100 parts by weight of polyolefin, 1 to 1 of red phosphorus
20 parts by weight, the expansiveness when rapidly heated (800 to 1000 ° C.) is 100 times or more with respect to the C-axis direction, and 1 to 30 of the thermally expansive graphite containing 80% or more of 80 mesh on by classification. A flame-retardant polyolefin-based resin composition, characterized by containing parts by weight. 2. The expansivity when rapidly heated (800 to 1000 ° C.) is 100 times or more in the C-axis direction with respect to 100 parts by weight of polyolefin, and 80 by classification.
1 to 3 of heat-expandable graphite containing 80% or more of mesh-on
A flame-retardant polyolefin-based resin composition comprising 0 part by weight and a phosphorus compound.