JPH0340739B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to flame retardant polyolefin compositions. More particularly, the present invention relates to such a composition comprising a polyolefin, certain modified polyolefins, and an ammonium salt of an inorganic acid coated with a polysiloxane. It is known that ammonium salts of inorganic acids having flame retardant properties (hereinafter referred to as flame retardant ammonium inorganic acids) are effective as flame retardants for synthetic resins, particularly polyolefins. For example, JP-A No. 48-83136, No. 51-
130445 and Special Publication No. 55-17777, however,
Known flame-retardant polyolefin compositions containing flame-retardant ammonium inorganic acids (hereinafter referred to as flame-retardant polyolefins) have the following drawbacks. In other words, the majority of flame-retardant inorganic ammonium acids are readily water-soluble;
If this material is added to polyolefin and kneaded and molded, poor appearance of the molded product (note: silver mark) may occur.When the molded product is brought into contact with water, flame-retardant inorganic acid ammonium will be eluted, and after this elution, The flame retardancy of the molded product decreases. Furthermore, molded products manufactured using flame-retardant polyolefin obtained by adding a large amount of ammonium to polyolefin have lower mechanical properties, especially impact strength, than molded products made from polyolefin without additives. There is a point. The present inventors have conducted extensive research to solve the above-mentioned problems with known flame-retardant polyolefins.
As a result, some or all of the base resin polyolefin was replaced with a modified polyolefin modified with carboxylic acid, carboxylic acid anhydride, or a vinyl or vinylidene compound having an epoxy group, and a flame-retardant inorganic acid ammonium powder was replaced with polysiloxane. The present invention was completed based on the knowledge that all of the above-mentioned problems could be solved by using a film that was subjected to post-coating curing treatment. As is clear from the above description, an object of the present invention is to provide a flame-retardant polyolefin with improved appearance, water resistance, and mechanical properties of molded articles. Other purposes will become clear from the description below.
The present invention has the following main configuration (1) and embodiment configurations (2) to (5). (1) Polyolefin 0-90% by weight, carboxylic acid,
5 to 95% by weight of a modified polyolefin obtained by modifying with a carboxylic anhydride or a vinyl or vinylideline compound having an epoxy group, and 5 to 70% by weight of an ammonium salt of a flame-retardant inorganic acid coated with polysiloxane and then cured. A flame-retardant polyolefin composition. (2) The composition according to item 1 above, wherein the ammonium salt of a flameproof inorganic acid is ammonium sulfate. (3) The composition according to the above item 1, wherein the modified polyolefin is modified by reacting a polyolefin with a carboxylic acid or a carboxylic anhydride. (4) The composition according to item 1, wherein the modified polyolefin is modified by reacting a polyolefin with a vinyl compound or a vinylideline compound having an epoxy group. The structure and effects of the present invention will be explained in detail below. (a) Polyolefin used in the present invention: Any polyolefin that can be used for manufacturing molded products can be used. Specifically, they include polyethylene (low density, medium-low density, and high density), polypropylene, polybutene-1, poly-4-methylpentene-1, and the like. These polyolefins include not only homopolymers but also copolymers with other olefins containing 50% by weight or more of the polymer portion consisting of the olefin. The amount of polyolefin blended in the composition of the present invention is 0 to 100% based on the total amount of the composition.
It is 90% by weight. If the amount is 0% by weight, use the corresponding modified polyolefin at 30% by weight or more. Further, in the case of 90% by weight, at least 5% by weight or more of modified polyolefin is blended. If more than 90% by weight of polyolefin is used, the amount of flame retardant inorganic ammonium and/or modified polyolefin will be insufficient, making it difficult to achieve the present invention. (b) Modified polyolefin used in the present invention: Polyolefin (including a copolymer pair) mentioned above (a)
Then, one or more of α, β-unsaturated carboxylic acid or its anhydride, and a vinyl or vinylidene compound having an epoxy group are graft-polymerized by a known method. Specific examples of the above-mentioned α,β-unsaturated carboxylic acids or anhydrides thereof include acrylic acid, methacrylic acid, maleic anhydride, and itaconic anhydride. Further, specific examples of vinyl or vinylidene compounds having an epoxy group include:
Mention may be made of glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, vinyl epoxide and vinyl cyclohexene oxide. The specific method of the graft polymerization mentioned above is as follows:
stomach. By using a radical initiator, b. Causes caused by radiation or ultraviolet irradiation; c. Oxidation by ozone or oxygen and d. Examples include those by mechanical kneading. The grafting rate (note: the ratio of the grafting agent linked to the graft polymer) by these graft polymerizations is not limited, but is preferably 0.01% by weight or more, preferably 0.1% by weight or more and 10% by weight, and 0.01% by weight.
If it is less than 10% by weight, the effect as a modified polyolefin is insufficient, and even if it exceeds 10% by weight, it is uneconomical because the amount of modified polyolefin cannot be reduced. C. Flame retardant inorganic acid ammonium used in the present invention: The raw acid is not particularly limited as long as it is an inorganic acid, but examples include phosphoric acid, sulfuric acid, boric acid, hydrochloric acid, hydrochloric acid, sulfamic acid and imidodisulfonic acid. can give. As the ammonium salt of these acids, ammonium sulfate, which has a decomposition temperature of 300° C. or higher and is stable at the polyolefin molding temperature, is particularly preferred. Its form is preferably a fine powder. D. Polysiloxane treatment of flame retardant ammonium inorganic acid: This treatment can be done by simply attaching polysiloxane to the surface of the fine powder of flame retardant ammonium inorganic acid; Water resistance is improved compared to polyolefin compositions containing powder. but,
A desirable treatment is to treat the fine powder with a curable polysiloxane, and then cure the polysiloxane to form a film of cured polysiloxane on the surface of the flameproof inorganic acid ammonium fine powder. The object of the present invention is to make the powder excellent in water repellency and water resistance. (e) Curable polysiloxane: The polysiloxane that can be used in the present invention includes a) a methylhydropolysiloxane that cures by dehydrogenation crosslinking in the presence of oxygen or moisture, and b) a copolymer of dimethylsiloxane and methylhydropolysiloxane. alkylhydropolysiloxane, c) a silicone varnish whose curing reaction is caused by dehydration condensation of silanol groups, d) an oligomer caused by ring-opening condensation, and e the above i~
Examples include modified products or co-condensates of (2).
In addition, f The above-mentioned polysiloxane can be used in combination with other surface treatment agents, such as fluororesin, paraffin, wax, or higher fatty acid metal soap. (f) Curing accelerator: The curing method of the curable polysiloxane in (e) above is by heat curing as in (g) below. However, by using a curing accelerator, a film of a cured polysiloxane product can be easily formed on the surface of the flameproof inorganic acid ammonium fine powder. Examples of hardening accelerators include dialkyltin dialkyl fatty acid salts such as dibutyltin stearate, dibutyltin octoate, and dibutyltin maleate, and metal soaps such as iron octylate and tin octylate. Also useful are acids, alkalis, amines, titanates or phorates. The ratio of curing accelerator to flame retardant inorganic acid ammonium is 0.2 to 5.0% by weight, and the curing accelerator is 0.005 to 0.5% by weight.
%. In fact, the proportion of inert solvent mentioned below is 5 to 30%.
It is. Conditions for polysiloxane coating treatment: The method for producing the flameproof inorganic acid ammonium coated with polysiloxane used in the present invention is roughly as follows. That is, first, a curable polysiloxane and a curing accelerator are dissolved in an inert agent to form a solution, and a fine powder of flameproof inorganic acid ammonium is added to the solution, and the solvent is removed by evaporation while mixing and kneading. The polysiloxane adhering to the surface of the fine powder is heated and hardened. The heat curing temperature is usually 130°C to 200°C, preferably 150°C to 180°C, and the curing time is not limited, but usually 10 minutes to 5 hours, preferably 30 minutes to 3 hours. If the heat curing temperature mentioned above is less than 130℃, the curing reaction will not proceed and the water resistance of the treated object will be insufficient.If it exceeds 200℃, the curing speed will be too fast and it will warp, making it difficult to coat uniformly. The object to be treated becomes colored, which is not preferable. The above-mentioned inert solvent is not limited, but from the viewpoint of safety, chlorinated solvents such as 1,1,1-trichloroethane and tetrachlorethylene are preferred. H. Mixing of various raw materials according to the present invention The polyolefin, modified polyolefin, and flameproof inorganic acid ammonium described above are mixed in predetermined amounts by a known method, and if necessary, the mixture is further pelletized to obtain a product. In this mixture, stabilizers, pigments, fillers and other additives which are incorporated into known polyolefin compositions can be used, if necessary. The blending ratio of the three constituent raw materials constituting the composition of the present invention is 0 to 90% by weight of polyolefin and 5% by weight of modified polyolefin, based on the total composition of the three types.
~95% by weight, flame retardant ammonium inorganic acid 5-70
Weight%. If the amount of modified polyolefin is less than 5% by weight, not only the mechanical properties of molded articles produced using this composition are insufficient, but also the flame retardance is insufficient. This suggests the existence of a complementary effect between the flame retardant inorganic acid ammonium and the modified polyolefin in the composition of the present invention. Furthermore, if the amount of modified polyolefin exceeds 95% by weight, it becomes impossible to blend the minimum required amount of flameproof inorganic acid ammonium. If the amount of flame retardant inorganic acid ammonium is less than 5% by weight, the flame retardant effect will be insufficient, and if it exceeds 70% by weight, the amount of polyolefin and modified polyolefin or olefin will be relatively reduced, making it difficult to use such a composition. The mechanical properties of molded articles formed using the composition deteriorate, and the composition loses its practicality. The present invention will be explained below with reference to Examples. The combustion test and water absorption test methods adopted in the examples are as follows. Flame retardancy was determined by the following flame test in accordance with the US UL standard, Subject 94. Combustion Test A specimen 6 inches long, 1/2 inch wide, and 1/16 inch thick is hung vertically in a room with no air movement, with the upper end fixed. Apply the flame of a Bunsen burner adjusted to produce a 3/4 inch blue flame for 10 seconds from the bottom edge of the specimen. After 10 seconds, remove the burner and record the burning time of the test piece after removal, and use this as the first ignition burning time. Immediately after the flame of the test piece is extinguished, apply a burner flame to the lower end of the test piece for 10 seconds in the same manner, and record the time until the flame extinguishes again, and use this as the second ignition combustion time. Also, place a piece of cotton one foot below the test piece and record whether the cotton ignites during the test with a drop of flaming resin. The above test is carried out on five test pieces, and the flame retardancy is determined as follows based on the test results. 94V-0: The maximum burning time is within 10 seconds, the average burning time of the five test pieces is within 5 seconds, and none of the five test pieces ignites cotton. 94V-1: Maximum combustion time within 30 seconds, average combustion time
Within 25 seconds, no cotton ignition 94V-2: Burning time is the same as 94V-1. However, at least one of the test pieces causes cotton to ignite. 94HB: Average burning time is 25 seconds or more or maximum burning time is 30 seconds or more. The water absorption rate was determined in accordance with ASTM D-570 as follows. A test piece measuring 2 1/2 inches long, 1/2 inch wide, and 1/8 inch thick was dried in an oven at 50°C for 24 hours, left to cool in a desiccator at 23°C for 3 hours, and then dried. Measure (A). After immersing the test piece in pure water at 23°C for 16 hours, wipe off any water droplets from the test piece with a dry cloth and weigh immediately (B). The above test is performed on three test pieces to determine the water absorption rate. Water absorption rate (%) = B-A/A x 100 Treatment of ammonium sulfate used in Examples: Polysiloxane treated ammonium sulfate A, B and untreated ammonium sulfate used in Examples were produced in the following manner. (1) Polysiloxane-treated product: A 100 parts of ammonium sulfate fine powder obtained by adding and pulverizing a small amount of silicic anhydride fine powder is placed in a kneader equipped with a heating device, and while stirring, 2.0 parts of methylhydrosiloxane and dibutyltin dioxane are added in advance. Add a solution of 1,1,1-trichloroethane in which 0.2 part of ate is dissolved little by little and mix thoroughly. Next, the temperature is increased to remove the solvent. The powder temperature was set at 160 to 165°C, and the powder was heated and stirred for 3 hours to allow a sufficient curing reaction, and then cooled to room temperature to produce the powder. (2) Polysiloxane-treated product: B A polysiloxane-treated product was produced in the same manner as polysiloxane-treated product A, except that silicone varnish (Toshiba Silicone TSR-116) was used instead of methylhydropolysiloxane. (3) Untreated product: C Manufactured by adding a small amount of fine silicic acid anhydride powder to ammonium sulfate and pulverizing it. Examples 1 to 8, Comparative Examples 1 to 6 Ammonium sulfate, modified polyolefin, and polyolefin were mixed in a Henschel mixer at a predetermined mixing ratio, and then melt-kneaded and pelletized in a 20 mmφ single-screw vented extruder. The pellets were molded into specified test pieces using a small injection molding machine (mold clamping pressure: 32 tons), and water absorption tests and combustion tests were conducted. The formulation and results are shown in the table Materials used Modified polyolefin (A) Maleic anhydride modified polypropylene (maleic anhydride 0.4% by weight) (B) Maleic anhydride modified high density polyethylene (maleic anhydride 1.0% by weight) (C) Green Didyl methacrylate modified polypropylene (glycidyl methacrylate 5.5% by weight) (D) Glycidyl methacrylate modified high density polyethylene (glycidyl methacrylate 6.0% by weight) Polyolefin high density polyethylene Melt flow index 5 g/10 min Specific gravity 0.965 Polypropylene Melt flow rate 10 g /10 minutes Specific gravity 0.903 [Table]

Claims (1)

[Claims] 1. 0 to 90% by weight of polyolefin, carboxylic acid,
5 to 95% by weight of a modified polyolefin obtained by modification with a carboxylic acid anhydride or a vinyl or vinylidene compound having an epoxy group, and 5 to 70% by weight of an ammonium salt of a flame retardant inorganic acid coated with polysiloxane and then cured. A flame-retardant polyolefin composition. 2. The composition according to claim 1, wherein the ammonium salt of a flameproof inorganic acid is ammonium sulfate. 3. Claim 1, wherein the modified polyolefin is modified by reacting a polyolefin with a carboxylic acid or a carboxylic acid anhydride.
The composition described in Section. 4. The composition according to claim 1, wherein the modified polyolefin is modified by reacting a polyolefin with a vinyl compound or a vinylidene compound having an epoxy group.