JPS61252256A - Flame-retardant propylene polymer composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which inhibits bleeding of flame retarder and gives moldings having excellent surface appearance, consisting of a propylene polymer, an acetyl group-contg. polymer, a halogen-contg. flame retarder and a flame-retardant aid. CONSTITUTION:100pts.wt. propylene polymer (A) such as propylene homopolymer or block, random or graft copolymer composed of a major proportion of propylene and a minor proportion of other copolymerizable monomers such as alpha-olefin, an unsaturated carboxylic acid (derivative) or an unsaturated organosilane, 3-50pts.wt. acetyl group-contg. polymer (B) such as ethylene/vinyl acetate copolymer having a vinyl acetate content of 10-90wt%, 1-100pts.wt. halogen-contg. flame retarder (C) [e.g. bis(2,3-dibromopropyl)ether of tetra bromobisphenol A], 0.5-50pts.wt. flame-retardant aid (D) (e.g. Sb2O3) and option ally, additives (E) such as reinforcing filler (e.g. carbon black), antioxidant, etc., are melt-kneaded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a propylene polymer composition with improved flame retardant bleed and a good surface appearance of molded articles.

(Prior Art) A flame-retardant material made by adding a flame retardant to a propylene polymer, which has excellent moldability and mechanical properties, is widely used in various fields.

However, compositions using halogen flame retardants in particular have the drawback that the flame retardant bleeds over time, impairing the surface appearance of the final molded product and also reducing flame retardant performance.

(Problems to be Solved by the Invention) The present invention aims to improve the drawbacks of the prior art, that is, the bleeding of halogen flame retardants, and aims to achieve this purpose by using a specific polymer in combination. He discovered and did it.

(Means for Solving the Problems) That is, the present invention provides ``100 parts by weight of a propylene polymer, 3 to 50 parts by weight of an acetyl group-containing polymer, 1 to 100 parts by weight of a halogen flame retardant, and 0 parts by weight of a flame retardant aid. .5 to 50 parts by weight of a flame-retardant propylene polymer composition.

(Work) The propylene polymer used in the present invention is a homopolymer of propylene, a majority of the weight of propylene, and other α-olefins (
(ethylene, silane, hexene, 4-methylpentene, etc.)
, unsaturated carboxylic acids or their derivatives, unsaturated organic silanes, and other copolymerizable monomers, such as block, random, or graft copolymers. Crystalline materials are preferred because they are highly practical.

Examples of the acetyl group-containing polymer used in the present invention include polyvinyl acetate, ethylene-vinyl acetate copolymer, partially saponified products thereof, and vinyl acetate graft polyolefin (polyethylene, polypropylene, etc.). This material preferably has a vinyl acetate content of 10 to 90.
Particularly preferred are ethylene-vinyl acetate copolymers having a vinyl acetate content of 15 to 70% by weight. These values were determined from the viewpoint of the bleeding improvement effect.

Examples of the halogen-based flame retardants used in the present invention include bis(2,3-dibromopropyl) ether of tetrabromobisphenol A, bis(2,3-dibromopropyl) ether of tetrabromobisphenol S, and tetrabromobisphenol A1. Decabromodiphenyl oxide, tris(2,3-dibromopropyl)isocyanurate, pentabromotoluene, tribromopropane, 2.
2-bis(4-hydroxy-S,S-C/como-phenyl)propane and the like.

The flame retardant aid used in the present invention is preferably an inorganic compound, such as antimony trioxide, antimony tetroxide, antimony pentoxide, sodium pyroantimonate, tin dioxide, barium metaborate, zinc borate, zirconium oxide. , molybdenum oxide, and the like.

The blending ratio of each of these essential components is as follows: propylene polymer i
3 to 50 parts by weight of the acetyl group-containing polymer, preferably 5 to 30 parts by weight, and 1 to 1 parts by weight of the above flame retardant per oo parts by weight.
0.00 parts by weight, preferably 2 to 50 parts by weight and flame retardant aids 0.5 to 50 parts by weight, preferably 1 to 25 parts by weight. From the viewpoint of effectiveness, it is more preferable that the amounts of the acetyl group-containing polymer and the flame retardant aid are each one-third or more of the flame retardant.

If the amount of the acetyl group-containing polymer is less than 3 parts by weight, the bleeding improvement effect will not be exhibited, while if it exceeds 50 parts by weight, the physical properties will deteriorate.

If the amount of the flame retardant is less than 1 part by weight, the flame retardancy will be poor, while if it exceeds 100 parts by weight, the strength of the supplement will decrease,
It is also an economic problem.

If the amount of the flame retardant aid is less than 0.5 parts by weight, the synergistic effect with the flame retardant will be small, while if it exceeds 50 parts by weight, the physical properties will deteriorate and it is not economically practical.

In addition to these essential components, the composition of the present invention may contain additional components within a range that does not significantly impair the effects of the present invention. For example, talc, mica,
Calcium carbonate, silica, glass fiber, etc. can be added. In addition, anti-aging agents, processing stabilizers, nucleating agents, lubricants, ultraviolet absorbers, antistatic agents, mold release agents, foaming agents,
Pigments, dispersants, etc. can also be added as necessary.

The method for producing the composition of the present invention is to mix a predetermined amount of the required components in a Banbury mixer, kneader, roll mill, single screw extruder, etc., as in the case of general propylene polymers.
It is obtained by melt-kneading using a twin-screw extruder or the like, but in some cases, a molded product can be obtained by directly putting the mixture of each component into a molding machine such as an injection, compression, or film molding machine.

(Example) In the examples shown below, the measurement of flammability is based on UL standard UL9.
It was carried out based on the method specified in 4.

Bleedability was evaluated using an injection molded sheet by the difference in gloss on the sheet surface determined by the following formula and by visual judgment. The gloss bleed property is good with a small difference in gloss.

Gloss difference = [Gloss before oven test] - (Gloss after being left in a 70℃ oven for 7 days) Visual judgment: Very much single bleed; × Much bleed; Δ Little bleed; Very little lobed; ○ No bleed t◎ Examples 1 to 3 and Comparative Examples 1 to 3 Using a propylene homopolymer with a melt of 70 and a rate of 8, a composition prepared according to the formulation shown in Table 1 was heated in a pressurized double-arm kneader manufactured by Moriyama Seisakusho. The mixture was kneaded at 200°C using -, and then made into a pellet using a pelletizer.

After that, this was molded into 80 x 120 x 2 cod sheet test pieces and flammability test pieces specified by UL94 using an injection molding machine manufactured by Toshiba Machine Co., Ltd. (IS90B model), and the bleedability and combustibility were evaluated. evaluated.

Examples 4 to 9 and Comparative Examples 4 to 8 Using an ethylene-propylene block copolymer (containing 6% by weight of ethylene) with a melt flow rate of 30 or a propylene homopolymer with a melt flow rate of 8, the formulations shown in Table 1 were prepared. After thoroughly mixing the composition prepared in a Henschel mixer, it was melt-extruded using a twin-screw extruder,
Pelletized using a pelletizer.

Evaluation was performed in the same manner as in Example 1 using this.

Margin below C)

Claims (1)

[Claims] Flame-retardant propylene comprising 100 parts by weight of a propylene polymer, 3 to 50 parts by weight of an acetyl group-containing polymer, 1 to 100 parts by weight of a halogen flame retardant, and 0.5 to 50 parts by weight of a flame retardant aid. Polymer composition.