JPS606740A - Flame-retarding polyolefin composition - Google Patents

Abstract

PURPOSE:The titled composition improved in appearance, water resistance and mechanical properties, comprising a polyolefin, a modified polyolefin, and a specified inorganic acid ammonium salt. CONSTITUTION:An inorganic acid ammonium salt coated with a polysiloxane is obtained adding an inorganic acid ammonium salt of a decomposition temperature >=300 deg.C (e.g., ammonium sulfate) to a solution formed by dissolving a curable polysiloxane (e.g., methylhydrogenpolysiloxane) and a cure accelerator (e.g., dibutyltin stearate) in an inert solvent, evaporating the solvent while kneading, and curing the kneaded mixture by heating at 130-200 deg.C for 10min-5hr. A composition is formed by mixing 0-90wt% polyolefin (e.g., PE) with 5-95wt% modified polyolefin containing 0.1-10wt% grafted carboxylic acid (anhydride) and 5-70wt% said coated ammonium salt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to flame retardant polyolefin compositions. More particularly, the present invention relates to such compositions 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, in JP-A No. 48-83138, No. 51-130445, and No. 55-17777, known flame-retardant polyolefin compositions (hereinafter referred to as flame-retardant polyolefins) containing flame-retardant ammonium inorganic acids contain It has the following drawbacks. In other words, the majority of flame-retardant inorganic ammonium acids are easily water-soluble, and if this is added to polyolefin and kneaded and molded, the molded product may have a poor appearance (note silver mark), and the molded product may not be When brought into contact with water, flame retardant inorganic acid ammonium is eluted, and the flame retardancy of the molded article after the elution is reduced. Furthermore, molded products made using flame-retardant polyolefin obtained by adding a large amount of flame-retardant ammonium inorganic acid to polyolefin have better mechanical properties, especially impact resistance, than molded products made from additive-free polyolefin. There is a problem that the strength decreases.

The present inventors 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 vinyl or vinylidene compound having a carboxylic acid, carboxylic acid anhydride, or epoxy group, and a flame-retardant inorganic acid ammonium powder was coated with polysiloxane and then cured. The present invention was completed based on the knowledge that all of the above-mentioned problems could be solved by using the above-described method.

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) A flame-retardant polyolefin composition comprising 70 to 80% by weight of Polio 17, 5 to 85% by weight of a modified polyolefin, and 5 to 70% by weight of an ammonium salt of an inorganic acid coated with polysiloxane.

(2) Item (1) above, wherein the ammonium salt of an inorganic acid coated with polysiloxane is obtained by surface treating and curing fine powder of an ammonium salt of a flame-retardant inorganic acid using a curable polysiloxane. The composition described in .

(3) The composition according to item (2) above, wherein the ammonium salt of a flameproof inorganic acid is ammonium sulfate.

(4) The composition according to item (1) above, wherein the modified polyolefin is modified by reacting a polyolefin with carporic acid or carpolic acid anhydride.

(5) The above-mentioned (1), wherein the modified polyolefin is modified by reacting a polyolefin with a vinyl compound or a vinylidene compound having an epoxy group.
The composition described in Section.

The structure and effects of the present invention will be explained in detail below.

B. Polyolefin used in the present invention: Any polyolefin that can be used for producing molded products can be used. Specifically, polyethylene (low density, medium-low density and high density).

These include polypropylene, polybutene-1 and poly-4-methylpentene-1. These polyolefins include not only homopolymers but also copolymers with other olefins containing 50% by weight or more of the polymer portion made of the olefin. The amount of polyolefin blended in the composition of the present invention is 0 to 80% by weight based on the total amount of the composition. (L, in the case of 0% by weight, 30% by weight or more of the corresponding modified polyolefin is used. In addition, in the case of 80% by weight, at least 5% by weight or more of the modified polyolefin is blended. If the amount of polyolefin exceeding 80% by weight is If used, the amount of flame retardant inorganic ammonium and/or modified polyolefin will be insufficient, making it difficult to achieve the present invention.

In the modified polyolefin used in the present invention, one or more of α, β unsaturated carboxylic acid or its anhydride, or a vinyl or vinylidene compound having an epoxy group is added to the above-mentioned polyolefin (including copolymerized pairs). Graft polymerization by method.

Specific examples of the aforementioned α,β-unsaturated carboxylic acid or its anhydride include acrylic acid, methacrylic acid, maleic anhydride, and itaconic anhydride. Further, specific examples of vinyl or vinylidene compounds having an epoxy group include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, vinyl epoxide, and vinyl cyclohexene oxide.

Specific methods for the above-mentioned graft polymerization include those using radical initiators, those using irradiation, radiation or ultraviolet irradiation, butylation using oxygen or oxygen, and mechanical kneading.

The grafting rate (note: the ratio of the grafting agent bonded 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.
If it is 0% by weight and less than 0.01% by weight, the effect as a modified polyolefin is insufficient, and if it exceeds 10% by weight, it is uneconomical because the amount of modified polyolefin cannot be saved.

C. Flameproof 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, and hydrochloric acid.

Examples include hydrochloric acid, sulfamic acid and imidodisulfonic acid. Ammonium sulfate, which has a decomposition temperature of 300'C or higher and is stable at the polyolefin molding temperature, is particularly preferred as the ammonium salt of these acids. Its form is preferably a fine powder.

2. 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, and even if this adhered product is used, no treatment is required. Water resistance is improved compared to polyolefin compositions containing fine powder.

However, 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 fine powder excellent in water repellency and water resistance.

(e) Curable polysiloxane: The polysiloxane that can be used in the present invention includes a) methylhydropolysiloxane which is cured by dehydrogenation crosslinking in the presence of oxygen or moisture, b) copolymer of dimethylsiloxane and methylhydropolysiloxane Examples include alkylhydropolysiloxanes such as silicone varnishes whose CO curing reaction is caused by dehydration condensation of silanol groups, cyclic oligomers caused by ring-opening condensation, and modified products or co-condensates of 80 or more yl. In addition, f. the above-mentioned polysiloxane with another surface treatment agent, ie, a fluororesin;

It can be used in combination with paraffin, wax or higher fatty acid metal soap.

c. Curing accelerator: The method for curing the curable polysiloxane described in e. above is described below.
By heat curing as in . 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 usage ratio of the curing accelerator to the flame retardant inorganic acid ammonium is 0.2 to 5.0% by weight, and the curing accelerator is exactly 0.
．． 005-0.5%. In particular, the proportion of the inert solvent mentioned below is 5 to 30%.

G. Conditions for polysiloxane coating treatment: The outline of the method for producing the flameproof inorganic acid ammonium coated with polysiloxane used in the present invention is as follows. That is, first, a curable polysiloxane and a curing accelerator are dissolved in an inert solvent 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! ~200'O preferably 15
The curing time is not limited, but is usually 10 minutes to 5 hours, preferably 30 minutes to 3 hours. The heat curing temperature mentioned above is 130'C! If the temperature is less than 200°C, the curing reaction will not proceed and the water resistance of the treated material will be insufficient.
If the curing speed exceeds 100%, the curing speed will be too fast, causing warping, making it difficult to coat uniformly, and in some cases, the object to be treated will be 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 aforementioned polyolefin, modified polyolefin, and flameproof inorganic acid ammonium 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 as 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, 5 to 95% by weight of modified polyolefin, and 5 to 70% by weight of flameproof inorganic acid ammonium, based on the total composition of the three types. It is. If the amount of modified polyolefin is less than 5% by weight, not only the mechanical properties of molded articles produced using this composition will be insufficient, but also the flame retardance will be insufficient. This suggests the existence of a complementary effect between the flameproof inorganic acid ammonium and the modified polyolefin in the composition of the present invention. Furthermore, if the amount of modified polyolefin exceeds 85% by weight, it becomes impossible to incorporate 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 modified olefin will be relatively reduced, and such a composition The mechanical properties of molded articles formed using the method 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 combustion test in accordance with the US UL standard, 5ubject 94.

Combustion Test Test specimens 6 inches long, 11 inches wide, and inches thick are hung vertically in a room with no moving air, with the upper end fixed. Apply the flame of a Bunsen burner adjusted to emit a blue flame of % inch for 10 seconds from the lower end of the test piece. After 10 seconds, the burner was removed, and the burning time of the test piece after removal was recorded, and this was taken as the first ignition burning time. Immediately after the flame of the test piece is extinguished, apply the 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.
This is 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. 5 or more tests
The flame retardancy is determined as follows based on the test results for wood test pieces.

94V-0: The maximum burning time is within 10 seconds, the average burning time of the 5 wooden test pieces is within 5 seconds, and none of the 5 wooden test pieces ignites cotton.

94V-1: Maximum combustion time within 30 seconds, average combustion time 2
Within 5 seconds, no cotton ignition 134V-2: Burning time is the same as 94V-1. However, at least one of the test pieces causes cotton to ignite.

94HB: Average combustion time is 25 seconds or more or maximum combustion time is 30 seconds or more.

The water absorption rate was determined as follows according to ASTM D-570.

A test piece with a length of 2 inches, a width of inches, and a thickness of inches is dried in an open oven at 50°C for 24 hours, left to cool in a desiccator at 23°C for 3 hours, and then weighed (A). After immersing the test piece in pure water at 23°C for 16 hours, wipe off the water droplets on the test piece surface with a dry cloth and weigh it immediately (B
).

The above test was conducted on three wooden test pieces to determine the water absorption rate.

C. Treatment of ammonium sulfate used in Examples: Polysiloxane treated ammonium sulfate A, B and untreated ammonium sulfate used in Examples were produced by the following method.

(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 was placed in a Nigu with a heating device, and while stirring, 2.0 parts of methylhydrosiloxane was added in advance.
1 part and 0.2 parts of dibutyltin dioctoate were dissolved.
, 1.14 Add the dichloroethane solution little by little and mix thoroughly. Next, the temperature is increased to remove the solvent. The powder was manufactured by heating and stirring at a temperature of 180 to 185° C. for 3 hours, allowing a sufficient curing reaction, and then cooling to room temperature.

(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 A small amount of fine silicic acid anhydride powder was added to ammonium diosulfate and pulverized.

Examples 1-8. 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 m 1 II φ single-screw bent n extruder. This pellet was molded into a predetermined test piece using a small injection molding machine (mold clamping pressure: 32 tons), and a water absorption test and a combustion test 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 (maleinoic anhydride 1.0% by weight) (G) Glycidyl methacrylate modified Polypropy 1/
(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% specific gravity Q, 9B5 Polypropylene melt flow rate 10% specific gravity o, so3

Claims (5)

[Claims] (1) A flame-retardant polyolefin composition comprising 0 to 90% by weight of polyoxy 24 foam, 5 to 85% by weight of a modified polyolefin, and 5 to 70% by weight of an ammonium salt of an inorganic acid coated with polysiloxane. (2) The ammonium salt of an inorganic acid coated with polysiloxane is obtained by surface-treating fine powder of an ammonium salt of a flame-retardant inorganic acid with a curable polysiloxane and then curing it. The composition according to item 1). (3) The composition according to claim (2), wherein the ammonium salt of a flameproof inorganic acid is ammonium sulfate. (4) The composition according to claim (1), wherein the modified polyolefin is modified by reacting a polyolefin with a carboxylic acid or a carboxylic anhydride. (5) The composition according to claim (1), wherein the f-formed polyolefin is modified by reacting a polyolefin with a vinyl compound or a vinylidene compound having an epoxy group.