JP2023183000A - Flame-retardant vinyl chloride resin composition - Google Patents

Abstract

To provide a flame-retardant vinyl chloride resin composition that exhibits superior flame retardancy with an oxygen index of 40% or more, and demonstrates hardness suitable for coating wires and cables.SOLUTION: A flame-retardant vinyl chloride resin composition contains a vinyl chloride resin, a plasticizer, and an inorganic flame retardant. Relative to 100 pts.mass of the vinyl chloride resin, the content of the plasticizer is 35-60 pts.mass and the content of the inorganic flame retardant is 70-100 pts.mass. The plasticizer is a mixture of general plasticizer and flame-retardant plasticizer. Relative to the total content of the mixture, the content of the flame-retardant plasticizer is 45 mass% or more. An oxygen index, as measured in accordance with JIS K 7201-2, is 40 or more.SELECTED DRAWING: None

Description

The present invention relates to a flame retardant vinyl chloride resin composition.

Conventionally, vinyl chloride resin compositions have been used as materials for molded products such as automobile parts and electronic/electrical equipment parts, and as coating materials for communication cables, electric wires, and the like. Flame retardancy is sometimes required for these molded product materials, coating materials, and the like. Examples of flame-retardant vinyl chloride resin compositions whose flame retardance is improved by containing an inorganic flame retardant include Patent Document 1.

Japanese Patent Application Publication No. 2019-070066

The oxygen index defined by JIS K7201-2 is known as an indicator of flame retardancy of plastic materials. Although the flame-retardant vinyl chloride resin composition disclosed in Patent Document 1 achieves an oxygen index of 35% or more, nothing has been disclosed that has an oxygen index exceeding 40% or more.

The present invention has been made in view of the above circumstances, and is a flame-retardant vinyl chloride resin composition that has excellent flame retardancy with an oxygen index of 40% or more and can exhibit hardness suitable for coating electric wires and cables. provide something.

[1] A flame-retardant vinyl chloride resin composition containing a vinyl chloride resin, a plasticizer, and an inorganic flame retardant, the plasticizer containing 35 to 60 parts by mass per 100 parts by mass of the vinyl chloride resin. parts by mass, and 70 to 100 parts by mass of the inorganic flame retardant, the plasticizer is a mixture of a general plasticizer and a flame-retardant plasticizer, and the flame-retardant plasticizer is added to the total content of the mixture. A flame-retardant vinyl chloride resin composition having a content of 45% by mass or more and an oxygen index of 40 or more as measured in accordance with JIS K 7201-2.
[2] The flame retardant vinyl chloride resin composition according to [1], when formed into a sheet, has a hardness of 95 or less after 10 seconds measured with a durometer type A according to JIS K 7215. Flame retardant vinyl chloride resin composition.
[3] The flame-retardant vinyl chloride resin composition according to [1] or [2], wherein the flame-retardant plasticizer is a phosphate ester plasticizer.
[4] The flame-retardant vinyl chloride resin composition according to any one of [1] to [3], wherein the inorganic flame retardant contains antimony trioxide, zinc borate, calcium carbonate, and metal hydroxide.
[5] The flame-retardant vinyl chloride resin composition according to any one of [1] to [4], which contains 6 parts by mass or more of antimony trioxide based on 100 parts by mass of the vinyl chloride resin.
[6] The flame-retardant vinyl chloride resin composition according to any one of [1] to [5], which contains 6 parts by mass or more of zinc borate based on 100 parts by mass of the vinyl chloride resin.

The flame-retardant vinyl chloride resin composition of the present invention has excellent flame retardancy with an oxygen index of 40% or more. In addition, it can exhibit hardness suitable for coating electric wires and cables.

≪Flame-retardant vinyl chloride resin composition≫
A first embodiment of the present invention is a flame-retardant vinyl chloride resin composition (hereinafter sometimes simply referred to as "PVC composition") containing a vinyl chloride resin, a plasticizer, and an inorganic flame retardant. be.
In the present embodiment, it is preferable that 35 to 60 parts by mass of the plasticizer and 70 to 100 parts by mass of the inorganic flame retardant are contained per 100 parts by mass of the vinyl chloride resin.
When the content of the inorganic flame retardant is within the above range, excellent flame retardancy can be obtained.
Since the content of inorganic flame retardant in the above range is relatively high, the hardness tends to be high, but by setting the content of plasticizer in the above range, hardness suitable for coating electric wires and cables can be obtained. be able to.

The plasticizer included in this embodiment is a mixture of a general plasticizer and a flame-retardant plasticizer, and the content of the flame-retardant plasticizer is preferably 45% by mass or more, and 48% by mass or more with respect to the total content of the mixture. It is more preferably at least 51% by mass, even more preferably at least 54% by mass, and most preferably at least 54% by mass. The upper limit is not particularly limited, but from the viewpoint of further enhancing the effect of the plasticizer and reducing hardness, it is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and 60% by mass. The following are most preferred.

Examples of general plasticizers include carboxylic ester plasticizers, epoxidized vegetable oils, and the like, with carboxylic ester plasticizers being preferred.
Examples of the carboxylic acid ester plasticizer include phthalic acid ester, terephthalic acid ester, adipic acid ester, trimellitic acid ester, citric acid ester, sebacic acid ester, azelaic acid ester, benzoic acid ester, and the like. Furthermore, low-molecular polyesters made of carboxylic acids and alcohols such as glycols, and polyesters such as phthalic acid polyesters can also be used as general plasticizers. The alcohol may be aliphatic, aromatic, or heterocyclic.

Examples of flame-retardant plasticizers include phosphate ester plasticizers, chlorinated paraffins, and chlorinated fatty acid esters. Agents are preferred.
Examples of phosphoric acid ester plasticizers include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris(2-ethylhexyl) phosphate, triphenyl phosphate, tricresyl phosphate, tricylenyl phosphate, cresyl diphenyl phosphate, and 2-ethylhexyl. Examples include diphenyl phosphate.

The inorganic flame retardant of this embodiment preferably contains four types: antimony trioxide, zinc borate, calcium carbonate, and metal hydroxide. As the metal hydroxide, aluminum hydroxide and magnesium hydroxide are preferred. Here, metal hydroxides are collectively treated as one type of inorganic flame retardant without distinguishing the type of metal. The number of metals constituting the metal hydroxide of this embodiment may be one, or two or more.
Although other known inorganic flame retardants may be included, a combination of the four types of inorganic flame retardants listed above can provide both excellent flame retardancy and hardness suitable for coating electric wires and cables. Therefore, it is most preferable to include only the above four types.
The inorganic flame retardant is usually contained in the form of particles, and the particle size can be, for example, about 0.1 to 30 μm.

As for the content of the four types of inorganic flame retardants in this embodiment, the content of antimony trioxide is preferably 6 to 20 parts by mass, more preferably 8 to 17 parts by mass with respect to 100 parts by mass of vinyl chloride resin. Parts by weight, more preferably 10 to 15 parts by weight. Further, the content of metal hydroxide is preferably 10 to 50 parts by weight, more preferably 20 to 40 parts by weight, and still more preferably 25 to 35 parts by weight. Further, the content of calcium carbonate is preferably 10 to 50 parts by weight, more preferably 20 to 40 parts by weight, and still more preferably 25 to 35 parts by weight. Further, the content of zinc borate is preferably 6 to 20 parts by weight, more preferably 8 to 17 parts by weight, and even more preferably 10 to 15 parts by weight.

Regarding the mass ratio of the four types of inorganic flame retardants in the present embodiment, (metal hydroxide/antimony trioxide) is preferably 1.0 to 5.0, more preferably 2.0 to 4.0, More preferably 2.5 to 3.5. Further, (calcium carbonate/antimony trioxide) is preferably 1.0 to 5.0, more preferably 2.0 to 4.0, and even more preferably 2.5 to 3.5. Further, (zinc borate/antimony trioxide) is preferably 0.5 to 2.0, more preferably 0.7 to 1.5, and even more preferably 0.8 to 1.2.

From the viewpoint of not only increasing the flame retardancy of the vinyl chloride resin composition of this embodiment but also achieving low hardness suitable for coating electric wires and cables, inorganic flame retardants and inorganic fillers other than the above four types (e.g. It is preferable that silicon oxide) is not included, or even if it is included, it is less than 1% by mass based on the total mass of the vinyl chloride resin composition.

The vinyl chloride resin of this embodiment may be a vinyl chloride homopolymer (PVC) or a copolymer. Examples of copolymerizable monomers include ethylene, propylene, acrylonitrile, vinyl acetate, maleic acid or its ester, acrylic acid or its ester, methacrylic acid or its ester, vinylidene chloride, and the like.
The vinyl chloride resin of this embodiment is preferably a vinyl chloride homopolymer. In the case of a copolymer, the content of repeating units other than vinyl chloride is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and 10 parts by mass or less with respect to 100 parts by mass of repeating units derived from vinyl chloride. More preferred.
The vinyl chloride resin of this embodiment may be chlorinated after resin formation.

The average degree of polymerization of the vinyl chloride resin of the present embodiment is not particularly limited, but is preferably, for example, 1,000 to 4,000, more preferably 1,300 to 3,000, and even more preferably 1,300 to 2,000. Within the above preferred range, it is easy to obtain a hardness suitable for coating electric wires and cables.
Here, the average degree of polymerization of the vinyl chloride resin is the average degree of polymerization measured in accordance with JIS K6720-2. The average degree of polymerization is calculated from the K value. The K value is a value measured in accordance with JIS K7367-2 (ISO1628-2).

The content of vinyl chloride resin based on the total mass of the PVC composition of the present embodiment is preferably 25 to 53 mass%, more preferably 30 to 50 mass%, even more preferably 35 to 48 mass%, and 40 to 45 mass%. % is most preferred. Within the above-mentioned preferred range, the blending ratio with other components will be appropriate and sufficient flame retardancy will be easily obtained.

The PVC composition of this embodiment may contain resins other than vinyl chloride resins, but from the viewpoint of fully obtaining the effects of the present invention, the content of resins other than vinyl chloride resins is It is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, based on 100 parts by mass of the system resin.

The PVC composition of this embodiment includes a heat stabilizer, a processing aid (lubricant), an ultraviolet absorber, a light stabilizer, an antioxidant, a crystal nucleating agent, and an antistatic agent, as long as the effects of the present invention are not impaired. Optional additives such as agents, metal deactivators, antibacterial agents, and pigments may be added.

Heat stabilizers include lead stabilizers, tin stabilizers, silver stabilizers, calcium-magnesium-zinc stabilizers, calcium-zinc stabilizers, barium-zinc stabilizers, and barium-cadmium stabilizers. , hydrotalcite stabilizers.
One type of heat stabilizer may be included, or two or more types may be included.
The total content of the heat stabilizer is preferably 1 to 10 parts by weight, more preferably 2 to 8 parts by weight, and even more preferably 3 to 7 parts by weight, based on 100 parts by weight of the vinyl chloride resin.

Processing aids include acrylic lubricants such as methyl acrylate and methyl methacrylate, fatty acid amide lubricants such as stearamide and oleic acid amide, and waxes such as paraffin wax, polyolefin wax, ester wax, montan acid wax, and polyethylene wax. higher fatty acids such as stearic acid and behenic acid, higher alcohols such as stearyl alcohol and cetyl alcohol, fatty acid esters such as butyl stearate and stearic acid monoglyceride, metal soaps such as calcium stearate and magnesium stearate, silicone oil, and procel oil. Oils such as
One type of processing aid may be included, or two or more types may be included.
The total content of processing aids is preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, and even more preferably 1 to 3 parts by weight, based on 100 parts by weight of the vinyl chloride resin.

<Method for manufacturing PVC composition>
The method for producing the PVC composition according to the present invention is not particularly limited, and it can be obtained by mixing and kneading in a conventional manner so that each component is uniform in the composition.
Examples of the method for mixing and kneading the vinyl chloride resin, plasticizer, inorganic flame retardant, etc. include a method using a pressure kneader, a Banbury mixer, or the like. When mixing, it is preferable to mix and knead at a resin temperature of 180° C. or lower from the viewpoint of preventing decomposition of PVC.

<Form of PVC composition>
The specific form of the PVC composition of this embodiment may be pellets, beads, or powder that can be easily subjected to other molding processes, or may be formed by known molding methods such as press molding, injection molding, and extrusion molding. It may also be a molded article formed by a method.
Molded products are not particularly limited, and include, for example, automobile parts, personal computers, electronic/electrical equipment parts such as copy machines, and covering materials for electric wires and cables.
The PVC composition of this embodiment has excellent flame retardancy and relatively low hardness, so it is particularly useful as a coating material for electric wires and cables.

<Physical properties of PVC composition>
(oxygen index)
The PVC composition of this embodiment was molded into a type IV test piece specified in JIS K 7201-2:2021, and the oxygen index was measured according to procedure A (top ignition) of JIS K 7201-2:2021. It is 40 or more. The upper limit of the oxygen index is not particularly limited, and a standard value is 50 or less.

(hardness)
The PVC composition of this embodiment is preferably molded into a sheet and has a hardness of 95 or less after 10 seconds as measured with a durometer type A in accordance with JIS K 7215:1986.
Here, the hardness after 10 seconds refers to a value measured 10 seconds after the indenter touches the surface of the test piece and starts pressing, and continues pressing. When the hardness after 10 seconds is 95 or less, it is particularly useful as a coating material for electric wires and cables.

(specific gravity)
The specific gravity of the PVC composition of this embodiment measured in accordance with JIS K 7112:1999 method A (underwater displacement method) is preferably 1.6 or less.

(Tensile strength)
The tensile strength of the PVC composition of this embodiment measured using test piece type 5 according to JIS K7127:1999 is preferably 14 MPa or more, more preferably 16 MPa or more, and even more preferably 18 MPa or more. The upper limit is not particularly limited, and may be, for example, about 30 MPa.

(Tensile elongation)
The tensile elongation of the PVC composition of this embodiment measured using test piece type 5 according to JIS K7127:1999 is preferably 150% or more, more preferably 200% or more, and even more preferably 220% or more. The upper limit is not particularly limited, and may be approximately 300%, for example.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

Details of the raw materials listed in Table 1 are as follows.
"PVC with a degree of polymerization of 1300" is TK-1300 manufactured by Shin-Etsu Chemical Co., Ltd.
The "Ca-Mg-Zn stabilizer" is ADEKA STAB RUP-103 manufactured by ADEKA. The "phthalic acid plasticizer" is DINP manufactured by J-Plus Co., Ltd., and is a general plasticizer.
The "trimellitic acid ester plasticizer" is W-700 manufactured by DIC Corporation, and is a general plasticizer.
The "phosphate ester plasticizer" is CDP manufactured by Daihachi Kagaku Kogyo Co., Ltd., and is a flame-retardant plasticizer.
The "acrylic processing aid" is Metablane P-551A manufactured by Mitsubishi Chemical Corporation.
"Antimony trioxide" is PATOX-M manufactured by Nippon Seiko Co., Ltd.
"Aluminum hydroxide" is Suisanka Aluminum BF013 manufactured by Nippon Light Metal Company.
"Calcium carbonate" is Whiten SB manufactured by Shiroishi Calcium Co., Ltd.
"Zinc borate" is ALCANEX FR-100 manufactured by Mizusawa Chemical Industry Co., Ltd.

<Preparation of composition>
Each raw material was mixed in the amounts (parts by mass) listed in Table 1 using a twin-screw kneader to obtain a PVC composition. For example, in Example 1, for 100 parts by mass of PVC, 5 parts by mass of stabilizer, 20 parts by mass of phthalate plasticizer, 25 parts by mass of phosphate plasticizer, 2 parts by mass of acrylic processing aid, 4 parts by mass of acrylic processing aid, A total of 80 parts by mass of the various inorganic flame retardants were blended to obtain the desired PVC composition.

<Creating a sheet>
100 g of the PVC composition of each test example was kneaded for 10 minutes using a 3.5-inch roll set at 155° C. to create a sheet with a thickness of 0.5 mm. Regarding the sheet created here, it is possible to distinguish between the direction in which the sheet is passed through the roll (flow direction) and the direction perpendicular thereto. Two sheets were prepared, stacked with the flow directions of each sheet crossing each other, preheated at 170°C for 4 minutes, heated and compression molded at 170°C and 15 MPa for 4 minutes, and then heated. While being pressed, the sheet was slowly cooled to room temperature (25° C.) to obtain a sheet having a predetermined thickness determined by each test, and the sheet was subjected to tests such as oxygen index and hardness.

<Measurement of oxygen index>
In accordance with JIS K 7201-2:2021, the oxygen index was measured according to procedure A (top ignition) using a type IV test piece specified by the same standard.

<Measurement of hardness after 10 seconds>
The durometer hardness was measured in accordance with JIS K 7215:1986 using a type A indenter defined by the same standard. The test piece used was a sheet prepared as described above, and the value was measured 10 seconds after the indenter touched the surface of the test piece and started pressing after performing the conditioning specified by the standard. was defined as "hardness after 10 seconds".

<Specific gravity>
Using the sheet prepared as described above, the specific gravity was measured using an electronic hydrometer MD-300S manufactured by Alpha Mirage.

<Tensile strength>
The 1 mm thick sheet prepared as described above was punched into test piece type 5 specified in JIS K 7127:1999, and the resulting test piece was left standing in an environment of 23 ± 1°C for 24 hours, and then the tensile strength was determined. was measured. The tensile strength was measured in accordance with JIS K 7127:1999 at a tensile speed of 200 mm/min.

<Tensile elongation>
The 1 mm thick sheet prepared as described above was punched into test piece type 5 specified in JIS K 7127:1999, and the obtained test piece was left standing in an environment of 23 ± 1 °C for 24 hours, and then the tensile elongation was measured. It was measured. The tensile elongation was measured at a tensile speed of 200 mm/min in accordance with JIS K 7127:1999.

The PVC composition of Example 1 has an oxygen index of 40 or more by containing 35 to 60 parts by mass of a plasticizer and 70 to 100 parts by mass of an inorganic flame retardant to 100 parts by mass of vinyl chloride resin. It showed excellent flame retardancy. In particular, since it contains approximately 56% by mass (25 parts by mass) of a phosphate ester plasticizer, which is an example of a flame-retardant plasticizer, based on the total content of plasticizers (55 parts by mass), the oxygen index is 40 or more. And the hardness became 95 or less after 10 seconds.
On the other hand, in the PVC composition of Comparative Example 1, the oxygen index did not reach 40 or higher because the content of the flame-retardant plasticizer was small. Further, in the PVC compositions of Comparative Examples 2 to 5, the oxygen index did not reach 40 or more due to the influence of the content of the inorganic flame retardant.
The PVC compositions of Reference Examples 1 and 2 had an oxygen index of 40 or more, but because they contained only either a general plasticizer or a flame-retardant plasticizer, the hardness was high after 10 seconds. However, the hardness was not suitable for coating electric wires and cables.

Claims (6)

A flame-retardant vinyl chloride resin composition comprising a vinyl chloride resin, a plasticizer, and an inorganic flame retardant,
35 to 60 parts by mass of the plasticizer and 70 to 100 parts by mass of the inorganic flame retardant are included with respect to 100 parts by mass of the vinyl chloride resin,
The plasticizer is a mixture of a general plasticizer and a flame-retardant plasticizer, and the content of the flame-retardant plasticizer is 45% by mass or more with respect to the total content of the mixture,
A flame-retardant vinyl chloride resin composition having an oxygen index of 40 or more as measured in accordance with JIS K 7201-2. The flame-retardant vinyl chloride resin composition according to claim 1, wherein the flame-retardant vinyl chloride resin composition has a hardness of 95 or less after 10 seconds as measured with a durometer type A in accordance with JIS K 7215. The flame-retardant vinyl chloride resin composition according to claim 1 or 2, wherein the flame-retardant plasticizer is a phosphate ester plasticizer. The flame-retardant vinyl chloride resin composition according to claim 3, wherein the inorganic flame retardant contains antimony trioxide, zinc borate, calcium carbonate, and metal hydroxide. The flame-retardant vinyl chloride resin composition according to claim 4, which contains 6 parts by mass or more of antimony trioxide based on 100 parts by mass of the vinyl chloride resin. The flame-retardant vinyl chloride resin composition according to claim 5, which contains 6 parts by mass or more of zinc borate based on 100 parts by mass of the vinyl chloride resin.