JPS61272252A - Flame-retardant water-proofing composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition free of generation of toxic gas because of the absence of halogen, having excellent water-proofing property and flexibility and suitable for filling in a cable, by compounding a phosphorus compound and cellulose and, if necessary, an inorganic filler, etc. CONSTITUTION:The objective composition can be produced by compounding (A) a phosphorus compound (e.g. phosphoric acid ester), (B) a cellulose (e.g. ethylcellulose, acetyl butyl cellulose, etc.), and if necessary (C) an inorganic filler having an average particle diameter of <=30mum (e.g. aluminum oxide) and/or (D) a low-molecular polyethylene having an average molecular weight of <=5,000. The ratios of the components A, B, C and D are preferably 40-90(wt)%, 2-30%, 15-50% and 2-7%, respectively.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a novel flame retardant waterproof composition.

(Prior Art) A waterproof composition has conventionally been filled into a waterproof object, such as a cable, to prevent moisture from entering. Known examples of such waterproof compositions include petrolatum-based sherry, polybutene-based sherry, and gel-like compounds made by mixing thermoplastic elastomer and process oil.

However, since the main component of each compound is easily flammable, it has the disadvantage that it easily ignites and burns. Therefore, it has been proposed to incorporate halogen and inorganic substances into the above-mentioned compound as a flame retardant formulation.

(Problems to be Solved by the Invention) However, the above-mentioned flame-retardant and waterproof compound still has problems that need to be improved. That is, Hunbound containing halogen is effective for flame retardation. However, this Hunbound has the problem of emitting toxic gas when burned, while the compound filled with inorganic substances such as aluminum hydroxide does not emit toxic gas, but the problem is that the compound is used inside the cable. Therefore, properties such as ease of filling, 1 dropping point, viscosity, flexibility at low temperatures, etc., required for this purpose cannot be satisfied. Therefore, there is a problem in that it is difficult to satisfy these characteristics and to make it flame retardant.

The present invention aims to provide a novel flame-retardant and waterproof composition that overcomes the drawbacks of conventional waterproof compounds.

(Means for Solving the Problems) In view of the above-mentioned current situation, the present inventors have proposed that the cable does not contain halogen, is easy to fill in the cable, does not drip within the operating temperature range, and does not contain halogen in the cable after filling. As a result of various studies aimed at developing a flame-retardant and waterproof compound that has no problems in terms of transmission and mechanical properties, we have arrived at the flame-retardant and waterproof composition of the present invention, which is comprised of a phosphorus-based compound and cellulose.

i9 The present invention provides a flame retardant waterproof composition comprising a phosphorus compound, cellulose and an inorganic filler as a second invention, and a flame retardant composition comprising a phosphorus compound, cellulose, an inorganic filler and polyethylene as a third invention. The present invention relates to a waterproof composition.

A particularly preferred embodiment of the present invention is that the phosphorus compound in each of the above compositions is a phosphoric acid ester, the content of the phosphoric acid ester is 40% by weight or less upwind of 90% by weight, and the inorganic filler. The agent is composed of one or more of the group consisting of aluminum hydroxide, magnesium hydroxide, magnesium carbonate and calcium carbonate, and the content of the inorganic filler is 15% by weight or more and 50% by weight or less, When the average molecular weight of polyethylene is 5,000 or less and its content is 2% or more and 7% by weight or less, cellulose is a cellulose ester, and cellulose is a cellulose ether color.
The content may be 2% by weight or more and 30% by weight or less.

The phosphoric esters used in the present invention include ate,
Examples include tricresyl phosphate, and particularly preferred is doaryl phosphate ester where R=Ar in the above general formula. Such acid esters are advantageous in that they are non-halogen, flame retardant, and do not significantly reduce the viscosity of the composition.

The content of phosphoric acid ester in the composition of the present invention is preferably 40% by weight or more based on the total composition amount, preferably 90% by weight, and if it is less than 40% by weight, the compound becomes putty-like or above 90% by weight. If the amount is exceeded, the phosphoric acid ester will separate.

Inorganic fillers used in the present invention include metal hydroxides such as aluminum hydroxide and magnesium hydroxide, which separate nonflammable gases, calcium carbonate and magnesium carbonate, and antimony trioxide, which improves flame retardancy. It is preferable because it has an effect.

The inorganic filler preferably has an average particle size of less than 30 μm. This is because if particles with an average particle size of 30 pm or more are used, the filler cannot be stably dispersed over a long period of time and will separate.

#The inorganic filler is preferably contained in a range of 5 to 50 parts by weight based on the total amount of the composition; if it is less than 5 parts by weight, the flame retardant effect will be low, and if it exceeds 50 parts by weight, The higher the viscosity, the more difficult it is to fill.

In the present invention, polyethylene is used to maintain the flexibility of the composition. Examples of such polyethylene include polyethylene wax.

In particular, it is preferable to use low molecular weight polyethylene having an average molecular weight of 5000 or less in order to increase the dropping point. The content of the polyethylene is preferably 2 parts by weight or more and 7 parts by weight or less based on the total weight of the composition. If it is less than 2 parts by weight, no flexibility effect can be expected, and if it exceeds 7 parts by weight, it is a flammable low molecular weight polyethylene. Therefore, the effect as a flame retardant and waterproof composition is lost.

Examples of cellulose that can be used in the present invention include:
Examples include cellulose ethers such as ether cellulose and methyl cellulose, and cellulose esters such as acetylphthyryl cellulose. In addition to imparting flexibility and toughness to the composition, cellulose has the advantage of low flammability. The content of cellulose is preferably 2 mft% or more and 30% by weight or less based on the total amount of the composition. If it is less than 2 mft%, it will be brittle and prone to cracking, while if it exceeds 30 mft%, the dropping point will be low. Put it away.

Incidentally, it is of course possible to mix a thickener, a coloring agent, or an antioxidant in order to adjust the viscosity into the flame-retardant and waterproof composition of the present invention.

(Example) Example Optical fibers coated with flame-retardant nylon were assembled, and the optical fiber assembly core was coated with a laminate T-tape and a polyethylene outer sheath, and an LP sheath was applied.
For optical fiber cables that passed the standard 758 test, the cable was filled with the composition of the present invention having the composition shown in Table 1 and one with a comparative composition, and each was subjected to the UL standard 758 test (flame retardant test) described below. ) and water permeability tests were conducted. The results are shown in Table 1 with a mark ○ indicating a pass and a mark X indicating a fail.

The units in the table are by weight.

Phosphate esters A and B have the general formula % formula % Here, the UL standard 758 test is applied to wiring materials for radios, televisions, etc. for export to the United States, and is a well-known method known as the "IFR-1 test". According to the configuration roughly shown in FIG. 1, the position of the chiril burner 4 is set so that the tip of the reducing flame 2 hits a position 762 mm from the lower end of the sample 1 having a length of 450 cm.

The length of the reduction flame 2 is approximately 35 m, the oxidation flame length is approximately 130 m, and the position of the indicator flag 5 is above 254a from the point of contact with the flame.
165.1 Lay surgical cotton 6 on the floor below the lower end of the sample. Repeat the operation of applying the flame for 15 seconds and pausing for 15 seconds 5 times, ■ The flame does not burn for more than 1 minute after the 5th exposure, ■ The flame loss of the indicator flag is less than %, ■ The surgical cotton does not burn due to the drippings. ,
Those who meet the ■items will be passed.

In a water permeability test to check the filling properties of a cable, the cable to be measured is cut to a length of 1 m and installed vertically, a 1 m hollow tube of the same diameter is connected above it, and water is poured into the hollow tube. We checked to see if water entered the lower cable under test and dripped from the other end of the cable, and if there was no dripping, we passed the test.

As is clear from the results in Table 1, the composition of the present invention exhibits excellent flame retardancy and waterproof properties when used in cables.

(Effects of the invention) As detailed above, the waterproofing compounds used in conventional cables were easily flammable, making it difficult to make them flame-retardant. It contains a halogen-containing compound that generates.

In contrast, the flame-retardant and waterproof composition of the present invention is composed of a phosphorus compound and cellulose, or in addition to these, an inorganic filler and/or low molecular weight polyethylene, and does not contain halogen, so no toxic gas is generated. It has great effects in that it can be flame retardant and does not interfere with cable properties such as waterproofness and flexibility, and can fully meet the demands of industries such as communications and electric power.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the UL standard 758 test method.

Claims (9)

[Claims] (1) A flame-retardant and waterproof composition comprising a phosphorus compound and cellulose. (2) A flame-retardant and waterproof composition comprising a phosphorus compound, cellulose, and an inorganic filler. (3) A flame-retardant and waterproof composition comprising a phosphorus compound, cellulose, an inorganic filler, and polyethylene. (4) The flame-retardant and waterproof composition according to any one of claims (1) to (3), wherein the phosphorus compound is a phosphate ester. (5) The flame-retardant and waterproof composition according to claim (4), wherein the content of the phosphoric acid ester is 40% by weight or more and 90% by weight or less. (6) Claims (2) or (3) in which the inorganic filler comprises one or more of the group consisting of aluminum hydroxide, magnesium hydroxide, magnesium carbonate, and calcium carbonate; Flame retardant and waterproof composition. (7) The flame-retardant and waterproof composition according to claim (6), which contains an inorganic filler in an amount of 5% by weight or more and 50% by weight or less. (8) The flame-retardant and waterproof composition according to claim (3), wherein the polyethylene has an average molecular weight of 5,000 or less and a content of polyethylene of 2% by weight or more and 7% by weight or less. (9) Claims (1) to (3) wherein the cellulose is composed of cellulose ester or cellulose ether, and the content thereof is 2% by weight or more and 30% by weight or less.
) The flame-retardant and waterproof composition described in any of the above items.