JPH10139967A - Low-smoke-generating resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-smoke-generating hard vinyl chloride-based resin compsn. which exhibits good heat resistance and moldability in molding and low-smoke-generating properties in a fire, and is used in applications such as transporting means such as airplanes ships, or vehicles; building materials such as interior or exterior materials, window frames and partitions; furniture and business tools; and housings of electric and electronic apparatuses. SOLUTION: This comps. is prepd. by compounding 100 pts.wt. vinyl chloride- based resin compsn. with at least 2 pts.wt. molybdenum compd. comprising molybdenum oxide and/or ammonium molybdate, at least 4 pts.wt. magnesium hydroxide, and 1-5 pts.wt. silicone powder, the sum of the molybdenum compd. and magnesium hydroxide being 25 pts.wt. or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transportation equipment such as aircraft, ships, vehicles, etc., interior and exterior materials of buildings, window frames, partitions, etc., furniture, office tools, and housings for home appliances and electronic equipment. More specifically, the present invention relates to a hard vinyl chloride resin composition having heat resistance during processing, moldability, and low smoke emission in a fire.

[0002]

2. Description of the Related Art In recent years, building resin materials are flame-retardant in response to the increase in height of buildings and the airtightness of living rooms. There has been a demand for the development of effective low-smoke formulations.
As to the hard vinyl chloride resin material, molybdenum trioxide (MoO ₃ ), ammonium octamolybdate ((NH ₄ ) ₄ Mo ₈ O ₂₆ ), zinc molybdate (ZnMoO ₄ or Zn ₃ ) are used as flame retardant smoke suppressants. Mo ₃ O ₉ ) is known. (Polymer Digest 1994.24 74-75) Further, talc or calcium carbonate is used as a core material, and two components of molybdenum and zinc, or molybdenum, zinc,
A finely powdered smoke suppressant containing three components, phosphorus and calcium, as active ingredients is on the market. (Kikuchi Color Co., Ltd. Bowen SK Series)

[0003] Hard vinyl chloride resin compositions are generally
No plasticizer is used, and high viscosity MBS or acrylic impact modifier (also known as reinforcing agent) is blended. Dibutyltin malate, which has poor lubricity, to ensure thermal stability Since a stabilizer is used, the processing temperature in the kneading and molding steps requires a much higher temperature than in the case of a so-called soft vinyl chloride resin composition, and may reach 200 ° C. or more. Under such high heat conditions, the zinc component functions as a thermal decomposition catalyst, easily causes coloration by heating, and makes it difficult to perform stable continuous processing for a long time. On the other hand, when such a composition is recycled, its thermal stability becomes a problem, and recycling becomes difficult. Also,
When only molybdenum oxide or ammonium molybdate is used as the smoke suppressant, the smoke suppressive effect on the hard vinyl chloride resin is low. Therefore, the present inventors have previously presented a specific range of composition with magnesium hydroxide in order to improve the smoke suppression of a molybdenum compound containing no zinc. (Japanese Patent Application No. 6-298938) In addition, the addition of silicone powder ("RM series" manufactured by Dow Corning Co., USA) to the thermoplastic resin reduces the smoke-generating property of the resin material at the time of combustion, and also reduces the moldability. In addition, there is a description that improvement in impact resistance can be expected and, as a specific example, a test result of a polypropylene resin composition.

[0004]

However, the combination composition of a molybdenum compound and magnesium hydroxide as described above is excellent in smoke-suppressing properties, but is not sufficiently satisfactory in molding workability and impact resistance. Needless to say, improvement was still desired. On the other hand, when only the above-mentioned silicone powder, or only silicone powder and magnesium hydroxide are blended into a hard vinyl chloride resin, the situation is quite different from the case of an olefin resin such as polypropylene, and the smoke emission is reduced. The extent was low.

In order to obtain a hard vinyl chloride resin composition having good moldability and impact resistance, in addition to a high level of smoke suppression, the present inventors have complemented the above two series of smoke suppressants. As a result of intensive studies on the properties, the above three types of smoke suppressants, namely, the molybdenum compound, magnesium hydroxide, and silicone powder, in a specific compounding range, the smoke suppressive effect of the conventional compound, a high level of smoke control that is hard to imagine And found that the moldability and impact resistance were maintained at good levels, thus completing the present invention.

[0006]

According to the present invention, at least 2 parts by weight of one or more molybdenum compounds of molybdenum oxide and ammonium molybdate are added to 100 parts by weight of a vinyl chloride resin composition. A low smoke-generating hard vinyl chloride resin composition comprising 4 parts by weight or more of magnesium hydroxide, a total amount of 25 parts by weight or less, and 1 to 5 parts by weight of silicone powder.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The vinyl chloride resin used in the present invention is preferably straight PVC having an average degree of polymerization in the range of 400 to 1,100. A multi-component copolymer resin with other copolymerizable monomers such as ethylene, ethylene and the like can be used.

As the molybdenum compound used in the present invention, molybdenum oxide and ammonium molybdate are used, and their average particle size is 0.3 to 5 μm, preferably 0.5 to 2 μm. If the average particle size is 0.3 μm or less, the viscosity of the resin composition increases, and molding processing becomes difficult. Further, since aggregation of the particles occurs, uniform dispersion cannot be achieved, and the impact strength is unfavorably reduced. Further, the compounding amount of the molybdenum compound is preferably at least 2 parts by weight (parts by weight indicate the compounding amount with respect to 100 parts by weight of the resin component. The same applies hereinafter), preferably 3 parts by weight or more. Can not be obtained.

The magnesium hydroxide used in the present invention has an average particle size of 0.5 to 20 μm, preferably 0.5 to 20 μm.
〜１０10 μm. When the average particle diameter is 0.5 μm or less, the viscosity of the resin composition increases, and molding processing becomes difficult. Also, since aggregation of the particles occurs, uniform dispersion cannot be achieved, and the impact is reduced. It is not preferable because it easily occurs. On the other hand, if the average particle size exceeds 10 μm, the smoke suppressing effect is undesirably reduced. The amount of magnesium hydroxide is at least 4 parts by weight, preferably 5 parts by weight or more. If the amount is less than 4 parts by weight, a good smoke suppression effect cannot be obtained.

If the total amount of these molybdenum compounds and magnesium hydroxide exceeds 25 parts by weight, there is a problem in practical use due to a decrease in ejection stability at the time of extrusion, a decrease in secondary moldability, particularly a decrease in impact resistance. It is not preferable because it is cold. In particular, in the case of a product where importance is placed on secondary moldability and impact strength, the total amount of these additives is preferably within 20 parts by weight. The silicone powder used in the present invention is obtained by introducing a phenyl group or an alkyl group into dimethylpolysiloxane for the purpose of improving compatibility with an organic resin, and has both compatibility and reactivity with the organic resin. It refers to a solid state in which an amino group, an epoxy group, a carboxy group, etc. are introduced.
In addition to the powder, a master pellet kneaded in a resin in advance can be used. The addition amount of the silicone powder is 1 to 5 parts by weight, preferably 2 to 4 parts by weight. If the added amount is less than 1 part by weight, the effect of suppressing smoke emission and the impact resistance are poor, and good results of secondary moldability cannot be obtained. Conversely, if the added amount exceeds 5 parts by weight, the lubricating property of the resin composition at the time of melting becomes excessive, sufficient kneading cannot be performed at the time of molding, and the molybdenum compound and magnesium hydroxide cannot be uniformly dispersed. It is not preferable because the suppression effect and the impact resistance decrease. In addition, the cost is not practical because silicone powder is expensive.

[0011]

The study of the mechanism by which the composition of the present invention exhibits additive smoke suppressing properties and maintains good levels in molding processability and mechanical properties of molded articles still requires research. However, not only the smoke suppression effect of the silicone powder is added, but also the dispersion of the molybdenum compound and the magnesium oxide in the resin is promoted by the interposition of the silicone powder, and the combination disclosed by the present inventors has been disclosed earlier. It is presumed that this is due to the fact that the smoke-suppressing effect of the compound was further improved. The hard vinyl chloride resin composition of the present invention, in addition to the above-mentioned additives, an impact resistance improver, a processability improver, a stabilizer, a lubricant,
Known compounding agents such as a coloring agent, a filler, and a plasticizer can be appropriately used. In addition, as a method for processing the rigid vinyl chloride resin composition of the present invention, all known methods such as an extrusion molding method, a calendar molding method, and an injection molding method can be applied.

[0012]

EXAMPLES The present invention will be described more specifically below with reference to examples, but the technical scope of the present invention is not limited to these examples. Examples 1 to 3, Comparative Examples 1 to 12, and Reference Examples The test smoke generating compositions shown in Tables 1, 2 and 3 below were mixed with the following base compositions, and using a 30 mm twin screw extruder,
After kneading, test specimens were prepared according to a predetermined method for each test. All the indicated compounding amounts are parts by weight based on 100 polymerized parts of the resin. (Base blend) Straight vinyl chloride resin (P = 1000) 100 Polyethylene wax lubricant 0.2 Acrylic reinforcing agent 15 Acrylic processing aid 3 Dibutyltin maleate 2 Fatty acid ester lubricant 1 (Content of test smoke generating agent) Molybdenum Ammonium acid Molecular formula (NH ₄ ) ₄ Mo ₈ O ₂₆ Molybdenum oxide Molecular formula MoO ₃ RM4-7105 Silicone powder manufactured by Dow Corning, USA (no reactive group) RM4-7081 Silicone powder manufactured by Dow Corning, USA (containing methacrylic group) The test method and conditions are shown.

I. Effect of Smoke Suppression (1) Smoke Emission The smoke emission is determined by the NBS smoke champer test (A).
An evaluation test was performed according to STM E-662-79). 76.2
mm x 76.2 mm test box completely closed box (eg:
914.4mm × 809.6mm × 814.4mm) supported vertically within the frame, the test piece 42.4Cm ²
Apply heat to the area. At this time, under the condition of fuming combustion, 1
Adjust so that 2.5 watts of heat is applied per cm ² . The light absorption of the light passing through the box by the smoke generated by combustion is measured using a standard photometer.
As the amount of smoke generated increases, so does the light absorption. The results were expressed as specific optical densities, which were determined in consideration of geometric factors in the measured values. The test this time was 4.0 after the start of combustion.
Comparison and judgment were made based on the results after minutes. Smoke emission sufficiently low for practical use is determined by the Ds specified in 25.853 of the Federal Aviation Regulations (FAR) defined by the United States Federal Aviation Administration (FAA).
The value of 4.0 is 200 or less. (2) Smoke suppression degree Ds4.0 value of the reference example (in the case of only the base compound) is B,
When the Ds4.0 value of the sample was A, (B−A) /
B × 100 (%) was set as the degree of smoke suppression, and was used as a quantitative comparison value of the effect.

II Thermal Stability Test A stability test was performed using a laboratory blast mill mixer manufactured by Toyo Seiki Seisakusho under the following conditions. Jacket temperature 190 ° C. Rotational speed 60 rpm Filling amount 80% of the jacket capacity The thermal stability was measured and compared with the time from the start of the decomposition of the resin molecules to the start of the increase in torque that appears as a result of a competitive reaction with radical crosslinking. Under the above conditions, the extrudability was determined to be good if the time was at least 15 minutes before the start of the torque increase.

III. Formability (1) Discharge stability: A sample having a discharge variation of 5% or less during extrusion processing is rated as ○. (2) Vacuum Formability The vacuum formability was confirmed using a vacuum pressure forming machine manufactured by Fuse Vacuum Co., Ltd.

IV Mechanical Properties Izod Impact Strength (ASTM D256) Test Results and Evaluation Tables 1, 2, and 3 summarize the test results.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3] As apparent from these results, for example, Example 1
The smoke suppression degree of the composition of the present invention significantly exceeds the sum of the suppression degrees of Comparative Examples 1 and 4 or the sum of the suppression degrees of Comparative Examples 2 and 3, which is a combination based on the conventional knowledge. The additive effect of the simultaneous addition of the three components of the test smoke suppressant is observed. In addition, heat resistance, molding workability, and mechanical properties are at good levels. The same is true for Examples 2 and 3.

[0020]

As described above, the composition of the present invention is a low-smoke hard vinyl chloride resin composition containing three types of smoke suppressants in a specific amount range. Has an unpredictable additive effect and has good thermal stability, moldability and mechanical properties, and is particularly suitable as a material for building materials.

Claims (2)

[Claims] 1. One or two or more molybdenum compounds of molybdenum oxide and ammonium molybdate are at least 2 parts by weight and magnesium hydroxide is at least 4 parts by weight based on 100 parts by weight of a vinyl chloride resin composition. A low-smoke-generating hard vinyl chloride-based resin composition having a total amount of not more than 25 parts by weight and further containing 1 to 5 parts by weight of a silicone powder. 2. The method according to claim 1, wherein the molybdenum compound is at least 3 parts by weight, the magnesium hydroxide is at least 5 parts by weight, the total amount thereof is within 20 parts by weight, and 2 to 5 parts by weight of silicone powder is further blended. A low-smoke-producing resin composition as described in the above.