CN1972536A - Fire-retardant type heating element applied for cryogenic stage self-regulating heating cable - Google Patents

Abstract

This invention relates to flame-proof heating element applied in low temperature automatic heating cable, which comprises fluorocarbon resin, polyester resin, and ethane and acrylic acid polymer, sensitizer for 5 to 15, inorganic filler, heat stabilizer, disperser, lubricant, flow agent and conductive agent. This invention materials form one stable flame-proof system with good effect after electron irradiation and with good anti-heat effect and good electricity property.

Description

Be applied in the flame retardant type heater element in the cryogenic stage self-regulating heating cable

Technical field:

The present invention relates to the flame retardant type heater element, more specifically saying so is applied in flame retardant type heater element in the cryogenic stage self-regulating heating cable.

Background technology:

The version of self controlled heating cable as shown in Figure 1, its section structure respectively as shown in Figures 2 and 3, be by a pair of stranded conductor as busbar 1, be semiconductor heating layer 2 in the outside of parallel busbar 1 with ptc characteristics; In the outside of heating layer 2 is insulating barrier 3, so constitutes the elementary cell of heating cable.

But, present existing heating temp is 70 ℃ ± 5 ℃ a low temperature level product, its ptc material that constitutes heater element generally is made up of polyolefinic synthetic mixtures, also promptly use polyethylene, haloflex, ethylene-acetate second resin copolymer etc. to be basis material, adopting oven process carbon black or acetylene carbon black is conductive agent, cooperate antioxidant, lubricant filler etc. constitute the PTC constituent.This class ptc material constituent is not fire-retardant, insulating barrier is set to have fire resistance when constituting heating cable with it, but in actual use, as external environment or power network fluctuation, variation, or be short-circuited once in a while, when causing cable breakdown, having spark occurs, this requires harsh occasion such as petrochemical industry project, petroleum pipeline, oil field, oil well for those, and scenes such as offshore oil platform are that strictness is forbidden, because of there is hidden danger in safety in utilization.

Summary of the invention:

The present invention is for avoiding above-mentioned existing in prior technology weak point, a kind of flame retardant type heater element that is applied in the cryogenic stage self-regulating heating cable is provided, both kept heat generation characteristic continual and steady, having good flame retardancy again, to satisfy the demand in market.

The technical scheme that technical solution problem of the present invention is adopted is:

Flame retardant type heater element of the present invention raw material by weight consists of:

Fluorocarbon-based resins: 50-70, polyester resin: 5-30,

Ethene and acrylic copolymer: 10-25, sensitizer: 5-15,

Inorganic filler: 30-50, heat stabilizer: 3-15,

Dispersant: 1-5, lubricant: 3-6,

Rheological agent: 1-3, conductive agent: 25-38.

The characteristics of flame retardant type heater element of the present invention also are:

Described fluorocarbon-based resins is homopolymers (PVDF), vinylidene fluoride and the hexafluoropropylene copolymer of vinylidene fluoride or the terpolymer of vinylidene fluoride and tetrafluoroethene and hexafluoropropylene;

Described polyester resin is the thermoplasticity polyester: polybutylene terephthalate (PBT);

Described sensitizer is TMPTMA, TAC or TAIC;

Described inorganic filler is a kind of in CaCO3, talcum powder, ZnO, MgO and the wollastonite;

Described heat stabilizer is antioxidant 1076 or 1010;

Described dispersant is PE wax or oxidation PE wax;

Described lubricant is a kind of among calcium stearate, zinc stearate, amide waxe and the EBS;

Described rheological agent is PA or PPA;

Described ethene and acrylic copolymer are EEA, EBA, EMA or EVA;

Described conductive agent is electrically conductive graphite, oven process carbon black or acetylene carbon black.

It is the PTC high flame retardant formula materials of Main Ingredients and Appearance that the present invention is provided with the fluorocarbon-based resins, in order to the core heater element that constitutes the high flame retardant self controlled heating cable to be provided.

On as two of busbar parallel zinc-plated or nickel plated copper wires, the raw mix of flame retardant type heater element of the present invention is moulded shape by the plasticating equipment refining, make grain, last mixing facilities further divides dispersing plasticizing, the grain that is shaped is extruded the PTC heater element (as shown in Figure 3) that forms dumbbell shaped through extruder again.Outside this heater element, extrude flame retardant insulation, and it is carried out cross-linking radiation.So, constituted the self controlled heating cable of the sustainable stable heating of fire resistance excellence.

Compared with the prior art, beneficial effect of the present invention is embodied in:

1, fire resistance of the present invention is good

Having adopted this basic flame resistance material fluorocarbon-based resins in the ptc material that the present invention's prescription provides is the formula mixture main body, cooperate sensitizer, fire-retardant filler, rheological agent and conductive agent again, the common cooperation formed a stable flame-retardant system, after the process electron radiation is crosslinked, has the good flame effect.

2, product good heat resistance of the present invention, electric performance stablity under the energising operating state.

The main body base material of mixture is a fluorocarbon-based resins in the PTC prescription of the present invention, this material melting point height, stable performance under the hot state, under the heating status of energising below 100 ℃, thermal stability is compared the conventional products that adopts polyolefine material (115 ℃ of fusing points, easy oxicracking under the hot state) to constitute in the existing procucts and is improved a lot.

Description of drawings:

Fig. 1 is the self controlled heating cable structural representation.

Fig. 2, Fig. 3 are the different section structure schematic diagram of self controlled heating cable.

Number in the figure: 1 busbar, 2 semiconductor heating layers, 3 insulating barriers.

Below pass through embodiment, and in conjunction with the accompanying drawings the present invention be further described:

Embodiment:

Referring to Fig. 1 and Fig. 3, concrete preparation operation according to the following procedure:

A, with seven diameters be 0, the tinned wird of 5mm carries out regular stranded shaping, constitutes pair of conductive bus 1.

B, carry out being mixed of ptc material raw material by following weight portion:

Fluorocarbon-based resins: 60 polyester resins: 25

Ethene and acrylic copolymer: 28 sensitizers: 5

Inorganic filler: 50 heat stabilizers: 8

Dispersant: 3 lubricants: 3

Rheological agent: 1 conductive agent: 36

The mixture of all raw materials is moulded shape by the plasticating equipment refining, makes grain, goes up mixing facilities again and further divides dispersing plasticizing, and grain is shaped; With busbar 1 is heart yearn, extrude into by extrusion equipment wide * thickly be 11,5 * 2, PTC heater element (shown in Figure 3) that 0mm has dumbbell shaped.

C, outside prepared heater element, extrude the flame retardant insulation 3 that thickness is 0.8mm, constitute heating cable.

D, crosslinked to carry out electron radiation through the prepared heating cable of step c.

The test of correlated performance:

Heating cable after electron radiation is crosslinked, intercepted length are the sample of 1M, test its main performance with following method, comprising:

1, resistance value

The sample of 1M was placed 4 hours in 20 ℃ of thermostats, used the resistance value between bridge measurement two busbars again.

2, heating temp

Between two busbars, add 220V voltage, after 5 minutes, measure temperature with thermosensitive thermometer.

3, anti-flammability (LOI)

Under room temperature state, sample is put in the oxygen index tester into the minimum oxygen content that test is provided when lighting.

4, cool and heat ends power cycles

Many samples that are cut into 1M are positioned over respectively on two sample frids of thermal stability test instrument cold junction (5 ℃) and hot junction (75 ℃), per 5 minutes circulation primary of hot and cold medium, with every voltage that all connects 220v of sample, every circulation is surveyed a power 30 times.

Test result is as follows:

1, fire resistance excellence of the present invention

Ptc material LOI value of the present invention reaches 48, and existing product LOI has only about 21.

2, product thermal stability of the present invention is better than existing procucts on the market.

The performance of existing procucts self controlled heating cable (ZKWD) is relatively on the present invention's example and the market:

Table one

Try routine item compared	The present invention	Mill run (ZKWD)
			Initial resistance (heating temp of Ω/m) (℃) anti-flammability (ptc material L01	645 76 48	480 72 21
Resistance value after 600 power cycles (heating temp of Ω/m) (℃) anti-flammability (LOI)	681 75 48	968 67 22

The present invention is applied in the flame retardant type heater element in the cryogenic stage self-regulating heating cable, and its raw material is by weight formed also can be listed as following table:

Group	PVDF	PBT	EEA	TMPTMA	ZNO	PE wax	Antioxidant	Lubricant	Rheological agent	Conductive agent
											1	70	5	14	15	45	5	3	3	3	38
2	50	30	25	5	40	1	15	6	1	25
											3	60	25	23	10	50	3	8	4	2	32
4	65	21	20	8	50	2、5	10	5	2、5	35

Claims (2)

1, be applied in flame retardant type heater element in the cryogenic stage self-regulating heating cable, it is characterized in that raw material by weight consists of:

Fluorocarbon-based resins: 50-70, polyester resin: 5-30,

Ethene and acrylic copolymer: 10-25, sensitizer: 5-15,

Inorganic filler: 30-50, heat stabilizer: 3-15,

Dispersant: 1-5, lubricant: 3-6,

Rheological agent: 1-3, conductive agent: 25-38.

2, flame retardant type heater element according to claim 1 is characterized in that:

Described fluorocarbon-based resins is homopolymers PVDF, vinylidene fluoride and the hexafluoropropylene copolymer of vinylidene fluoride or the terpolymer of vinylidene fluoride and tetrafluoroethene and hexafluoropropylene;

Described polyester resin is the thermoplasticity polyester: polybutylene terephthalate PBT;

Described sensitizer is TMPTMA, TAC or TAIC;

Described inorganic filler is a kind of in CaCO3, talcum powder, ZnO, MgO and the wollastonite;

Described heat stabilizer is antioxidant 1076 or 1010;

Described dispersant is PE wax or oxidation PE wax;

Described lubricant is a kind of among calcium stearate, zinc stearate, amide waxe and the EBS;

Described rheological agent is PA or PPA;

Described conductive agent is electrically conductive graphite, oven process carbon black or acetylene carbon black.

Described ethene and acrylic copolymer are EEA, EBA, EMA or EVA.