JP3384151B2 - Olefin-based conductive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to a road heating system.
Heating, roof heating, floor
Heating and other components used to prevent freezing
Conductive resin composition used for heating rod or linear heating member
About economics, productivity, extrusion, etc.
A composition with excellent moldability, especially self-temperature controllability
You. [0002] 2. Description of the Related Art A conductive filler is added to a polypropylene resin.
The compounded conductive resin composition has a
Heat generated by the heat of
The passing current is controlled by the volume change during the solution behavior,
Self-temperature controlled heating with temperature control function
It is being developed as a body. That is, the passing current is controlled to determine the Joule heat,
The temperature control function generates heat as the temperature rises.
As the volume resistivity of the feature increases,
The physical properties inherent to the heating element composition, which makes it difficult to suppress the amount of heat generated, are large
It is making a significant contribution. Therefore, the temperature of the heating element material
The responsiveness of changes in volume resistivity to changes
It is one of the important performances to get the accuracy of the roll.
It is. Low control accuracy reduces heat generation
Immediate response, rapid rise in temperature, and, in some cases,
Because it may cause disasters,
Is a material with high temperature control accuracy
Is desired. That is, the volume intrinsic resistance is sensitive to a change in temperature.
Conductivity for heating element with variable resistance and precise control of passing current
There is a demand for the appearance of a sexual composition. Such heating control
Various techniques have been proposed in the past to improve
ing. For example, in Japanese Patent Application Laid-Open No. 54-16697,
30% by weight or more of conductive carbon black (Example
, A polymer composition containing 42.6% by weight) is provided.
It has been proposed that carbon black is
Is problematic in extrusion moldability during molding.
In addition, the mechanical properties are inferior,
Deficiency due to handling during floor construction and external stress after construction
Problems such as loss remain. Also expensive conductive
Mixing carbon black at a high concentration is
Even so, it becomes expensive and has economical problems. Also,
Proposal of material using crosslinkable monomer as other technology
(Japanese Patent Application Laid-Open No. 3-143938)
Problems in productivity and economy due to the need for a bridge process
Is left. [0005] SUMMARY OF THE INVENTION The object of the present invention is to
To solve the problems of the conventional technology
Excellent mechanical properties and heat generation at normal temperature of 100 ° C or less
Temperature control accuracy higher than conventional as a conductive material
To provide an olefin-based conductive resin composition comprising
It is in. [0006] Means for Solving the Problems The present inventors have solved the above problems.
As a result of intensive research to solve the
Coalescing, using a specific ethylene polymer,
Exothermic temperature control by adding rack and flake graphite
Conductive tree with excellent trolling, mechanical strength and moldability
The present inventors have found that a fat composition can be obtained and have reached the present invention. That is, the present invention provides a melt flow rate
(MFR) is 3-80 g / 10 min and ethylene content is 1
Α-olefin containing 10 to 10% by weight and 4 to 12 carbon atoms
Propylene polymer (A) 1 having an amount of 0 to 10% by weight
00 parts by weight,as well as0.920 g / cm density^ThreeAnd more
Melt flow rate (MFR) is 0.5 to 40 g / 10
10 to 120 parts by weight of an ethylene polymer (B),
AndAverage particle size of 20mμm or more and BET specific surface
Product is 500m^Two/ G or more of carbon black (C) and
Graphite with an average particle size of 5 to 40 μm (D)The
With respect to 100 parts by weight of the total amount of the component (A) and the component (B)
hand10 to 50 parts by weight and20-100 weight in total
Olefin-based conductive tree characterized by blending parts
The present invention relates to a fat composition. Hereinafter, the present invention will be described in detail. (1) Each component and amount of resin composition   Propylene polymer [component (A)] The present invention relates to a melt flow rate [MFR; JIS K7
210 (230 ° C, 2.16 kg load)]
80 g / 10 min, preferably 10 to 50 g / 10 min.
15 to 40 g / 10 min, ethylene content 1
Α-olefin containing 10 to 10% by weight and 4 to 12 carbon atoms
Using a propylene-based polymer (A) in an amount of 0 to 10% by weight
You. Use an MFR of less than 3 g / 10 minutes
Extrusion molding when processing into molded products due to low fluidity
Etc. becomes difficult. On the other hand, if it exceeds 80 g / 10 minutes
When used, it has low viscosity when melted, so
In this case, shaping is difficult, which is not preferable. Also, ethylene
If the content is less than 1% by weight, molding is not possible due to poor flexibility.
It is not preferable as a material. On the other hand, ethylene or α-ole
When the fin exceeds 10% by weight, heat resistance becomes poor and heat is generated.
Suitable as a propylene copolymer for molding
Not in. [0010] Ethylene polymer [component (B)] The ethylene polymer (B) used in the present invention has a density (JIS
  0.920 g / cm according to K6760)^ThreeThat's all
Default flow rate [MFR; in accordance with JIS K6760
(190 ° C., 2.16 kg load)] is 0.5 to 40 g /
Add 10 minutes to 100 parts by weight of component (A)
To 120 parts by weight, preferably 15 to 80 parts by weight, furthermore
Preferably, 20 to 40 parts by weight are used. Less than 10 parts by weight
Is not preferable because the current control performance is low. Ma
Heat resistance is reduced when the amount exceeds 120 parts by weight.
However, it is not preferable as the material of the heat generating molded body. Also, 0.
MFR of less than 5 g / 10 min or more than 40 g / 10 min
Mechanical properties deteriorate when using ethylene polymer
(Especially tensile properties) are not preferred. MFR is 5
Particularly preferred is one having a flow rate of １５15 g / 10 min. The density is 0.920 g / cm^ThreeEchile less than
The use of olefin polymers lowers the heat resistance of the
Heat generation temperature controllability, passing current control
Poor control is not preferred. Density is 0.950 to 0.96
0 g / cm^ThreeAre particularly preferred. Also, ethylene-based
Polymers include polyethylene, ethylene and a small amount of carbon.
Α-olefins of numbers 3 to 12, for example, propylene, butene
Includes copolymers of
From the viewpoint of high crystallinity is preferred, and polyethylene
In particular, high density polyethylene is preferred. Carbon black [component (C)] Carbon black imparts conductivity to the composition and provides current resistance
In order to reduce the The carb black is
Average particle size 20mμm or more and BET specific surface area 500m
^Two/ G or more, preferably 25 to 30 m in average particle size
μm and BET specific surface area 500-900m^Two/ G high
Conductive carbon black is used. Average particle size is 20mμ
m, the carbon black
Difficult to disperse the resin in the resin, poor conductivity, poor appearance
Good or the like is likely to occur, which is not preferable. In addition, carbon black
Rarely exist as simple spherical particles
Primary particles are present as fused and aggregated aggregates
However, the average particle size here is not an aggregate, but a primary particle.
Mean particle size. The BET specific surface area is
500m^Two/ G of carbon black is essential for the present invention.
In order to obtain the necessary conductivity, a large amount must be blended.
As a result, the mechanical properties of the composition are reduced.
Not suitable for The carbon used in the present invention
Black has the following manufacturing method to reduce impurities.
Those obtained are preferred. That is, liquid hydrocarbons are
Oxidation reaction with molecular oxygen and water vapor
To produce highly conductive carbon at the same time as synthesis gasification.
The weight ratio of carbon atoms / hydrogen atoms of the hydrocarbon
And the furnace temperature is 1300 to 1450
In the range of ° C., the furnace pressure is 20-120 kg / cm^Two, Furnace
The amount of steam supplied into the tank is 4 per ton of the hydrocarbon.
Carbon black manufactured under the condition of 00 to 800 kg
Is preferred. The carbon atom / hydrogen atom weight of the hydrocarbon
Carbon black produced using one having a ratio of less than 9
Is a book that requires long-term heat resistance due to poor heat aging resistance.
Not preferred for the invention. Scale-like graphite [(D) component] In the present invention, a conductive filler other than the component (C) is used.
Average particle size of 5 to 40 μm, preferably 10 to 20 μm
Flake graphite (D) is used. Mixing the component (D)
The reason is that the rate of increase in electrical resistance increases with the rise in temperature of the resin composition.
This is for increasing the current control performance. The graphite is available in both natural and artificial forms.
Although it is possible to use any of them,
it can. When using flaky graphite with an average particle size of less than 5 μm
In this case, the electric resistance is so large that it is difficult for the current to flow,
It is not preferable as a charge. On the other hand, the average exceeding 40 μm
When flaky graphite having a particle size is used, the impact strength and
Mechanical strength such as tensile elongation is undesirably reduced. The above carbon black is used as a conductive filler.
K (C) component alone or the above flaky graphite (D) component
Is not preferred. That is, the component (C) alone
In the case of compounding, the rate of increase in electric resistance with respect to temperature is small
Current controllability and heat generation temperature control accuracy
Lowering and the flow characteristic of conductive carbon black
Problems such as reduced mechanical strength and reduced mechanical strength.
You. When the component (D) is used alone, the heating element is used.
Requires a large amount of compound to obtain the required conductivity.
It is not preferable because the mechanical strength is lowered. Follow
Good electrical conductivity as heating element, electrical resistance to temperature
To obtain the rate of increase, mechanical strength, moldability, etc.
It is preferable to use the above components (C) and (D) in combination.
No. The amount of component (C) and component (D) The carbon black (C) of the present invention and the flaky graphite (D)
The blending amounts are propylene polymer (A) and ethylene polymer
20 to 20 parts by weight with respect to 100 parts by weight of the total amount of the body (B)
100 parts by weight, preferably 28 to 80 parts by weight, particularly preferred
Or 36 to 60 parts by weight. Less than 20 parts by weight
Electricity is poor, so electric resistance is large and current does not easily flow
And it is difficult to generate heat, which is not preferable. Meanwhile, 1
If it exceeds 00 parts by weight, the fluidity of the composition at the time of melting
Deterioration makes molding difficult, mechanical strength such as toughness
And the productivity is lowered. Also
Carbon black is expensive, so mix it in large amounts
This is not economically favorable. Further, carbon black (C), flaky graphite
The mixing ratio (C / D) of (D) is said to control the passing current.
In view of the above, a result in which a weight ratio of 1/1 to 1/2 is preferable is
can get. Further, from the viewpoint of the effects in the present invention,
Component (C) and component (D) are each preferably less than 10 parts by weight.
It is not preferable to use more than 50 parts by weight for each.
No. Other additional components In addition to the above essential components, in the present invention the following
Such various additives can be used. Antioxidant
As tetrakis [methylene-3- (3 ', 5'-di-
t-butyl-4-hydroxyphenyl)Propionet
G) methane, A model represented by butylhydroxytoluene
Nophenol, polyhydroxybenzene, bisphenol
Phenol, trisphenol, tetrakisphenol, etc.
Toluene-based tetrakis (2,4-di-t-butylphenyl)
Enyl) -4,4'-biphenylenediphosphoKnight,
Tris-(2,4-di-t-butylphenyl) phospha
Monophosphite, diphospha
Site, triphosphite, tetraphosphite,
Phosphorus materials such as polyphosphite, girauli
-3,3'-thiodipropionate, pentae
Risulitol tetra (β-laurylthiopropione
G) Thiodipropionic acid S represented by esters
Sulfur-based oxidation of ter, thiopropionamide, etc.
The inhibitor is added to 100 parts by weight of the total amount of the components (A) to (D).
And 0.1 to 2 parts by weight. Further, as a metal deactivator, N, N'-
Bis [3- (3,5-di-t-butyl-4-hydroxy
Phenyl) propionyl] hydrazine, 3- (N-sali)
Representative of tyroyl) amino-1,2,4-triazole
(A)-(D)
0.1 to 2 parts by weight based on 100 parts by weight
Can be As filler dispersants, fatty acids,
Metal soap consisting of a metal salt of rubonic acid is used as a component (A) to (D)
0.1 to 2 parts by weight based on 100 parts by weight of the total amount of
be able to. These additives are used for resin
Suppression of component deterioration, suppression of deterioration promotion by contact with metal electrode
Unique to the present invention to control
Additives, each additive less than 0.1 parts by weight
Cannot achieve these effects, and the blending exceeds 2 parts by weight.
Once these effects reach saturation, further effects are expected.
I can't wait. (2) Physical properties of the composition Volume resistivity Observation of the temperature distribution of the heating element revealed that the volume resistivity was large.
It was found that the more unpleasant, the more uneven. Therefore, various
As a result of the examination, the volume resistivity at room temperature was 10¹Ω
・ The heating element consisting of a composition of not more than cm
It showed uniform heat generation and was confirmed to be preferable. Melt flow rate (MFR) In order to obtain good moldability, the MFR of the composition [JIS
  K7210 compliant (230 ° C, 5kg load)] is 0.1
It is preferably 10 to 10 g / 10 minutes. MFR is 0.
If it is less than 1 g / 10 minutes, the load at the time of extrusion molding is large.
Shape tends to be difficult, while exceeding 10 g / 10 min
In this case, the melt tension tends to be low and the shapeability tends to be lacking. Mechanical strength Regarding mechanical strength, a tensile strength and elongation test (JIS 71
13) and elongation at break at 20% or more and at break
Strength is 250kg / cm^TwoThe above is the construction of the heating element
It is preferable in handling at the time. (3) Preparation of composition The olefin-based conductive resin composition of the present invention, the above
Each of the components (A) to (D) and, if necessary, other components
Is obtained by mixing and kneading the additional components in a specific ratio.
Kneading and mixing equipment include twin screw extruders, pressure kneaders,
A Barry mixer or the like is used. Kneading temperature is 200 ~
In the range of 250 ° C., the kneading time is suitably 3 to 5 minutes. (4) Forming The conductive resin composition obtained by the above manufacturing method is plate-like, rod-like, etc.
Single-layer or multi-layer structure for various shapes
It is processed and used as a heating element. Extrusion machine
Types can be used depending on the application, and the processing temperature during molding
A suitable temperature is 180 to 230 ° C. [0026] 【Example】 (Ingredients) (1) Propylene-based polymer [component (A)] Propylene-ethylene copolymer: Mitsubishi Chemical
Polypropylene ”(fluorene content is 93% by weight, ethylene content is
7% by weight, MFR is 30g / 10min) Propylene-ethylene copolymer: Mitsubishi Chemical
Polypropylene ”(fluoropolyethylene content is 94% by weight, ethylene content is
6% by weight, MFR is 5g / 10min) Propylene-ethylene copolymer: Mitsubishi Chemical
Polypropylene ”(fluoropolyethylene content is 94% by weight, ethylene content is
6% by weight, MFR 2 g / 10 min) Propylene-ethylene copolymer: Mitsubishi Chemical
Polypropylene ”(fluorene content is 93% by weight, ethylene content is
7% by weight, MFR 100g / 10min) (2) Ethylene polymer [component (B)] Polyethylene: Mitsubishi Chemical's “Mitsubishi Polyethylene” (density
Is 0.951 g / cm^Three, MFR is 9g / 10min.
Ethylene) Polyethylene: Mitsubishi Chemical's “Mitsubishi Polyethylene” (density
Is 0.918 g / cm^Three, MFR of 5 g / 10 min.
Ethylene) Polyethylene: Mitsubishi Chemical's “Mitsubishi Polyethylene” (density
Is 0.930 g / cm^Three, MFR of 5g / 10min
Ethylene) (3) Carbon black [component (C)] EC Carbon: Mitsubishi Chemical's "EC Carbon" (average grain
Diameter 30mμm, BET specific surface area 800m^Two/ G
Carbon black) Acetylene black: Denka Black manufactured by Denki Kagaku
(Average particle size is 50mμm, BET specific surface area is 70m^Two
/ G of carbon black) (4) Flake graphite [(D) component] Flaky graphite: "Graphite CPB" manufactured by Nippon Graphite Industries (average grain
(The diameter is 10μm) Flake graphite: Graphite CB100 manufactured by Nippon Graphite Industries (average
(Particle size is 50μm) [Example 1] Propylene-ethylene as propylene polymer (A)
100 parts by weight of the copolymer, ethylene polymer (B) and
And polyethylene to 100 parts by weight of component (A)
0 parts by weight, as carbon black (C)EC carbon
With respect to 100 parts by weight of the total of the components (A) and (B).
0 parts by weight, scaly graphite as scaly graphite (D)
30 parts per 100 parts by weight of the total of the components (A) and (B)
Parts by weight, tetrakis [methylene-3-
(3 ', 5'-di-tert-butyl-4-hydroxyphenyl)
Le) propionate] methane (Ciba Geigy “Il
Ganox 1010 "), the total of components (A) to (D) being 100
0.1 parts by weight based on parts by weight, pentaerythritol tet
La (β-lauryl-thiopropionate) ester (white
"Seanox 412S" manufactured by Ishi Calcium Co.)
1 part by weight, N, N'-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyl] hydrazine (Irga, manufactured by Ciba-Geigy)
Knox MD1024 ”) in the same way
As a powder, magnesium stearate (“S
M # 1000 ”), 0.3 parts by weight, L / D = 30,
The coaxial twin screw extruder with a diameter of 30 mm
Melt and mix at 0 ° C and screw rotation speed of 220 rpm
Kneaded pellets were obtained. L / D = 15, mouth
Put into a single screw extruder with a diameter of 20 mm, and 6 mm x 200 m
m (length) into a single-layer rod shape and shown below as a heating element
The method was evaluated. Table 1 shows the results. [Evaluation method] (1) PTC characteristics (Positive Tempera)
cure Coefficence) Current (I) flowing when a constant voltage (E) is applied to the above-mentioned molded body
And the accompanying temperature of the heat-generating molded body surface is measured. And
Calculate resistance (R) according to Ohm's law (R = E / I)
Then, a correlation curve (PTC curve) between the surface temperature and the resistance is obtained.
The PTC curve for a good heating element is the normal temperature before heating.
In the region, it has low resistance, current flows easily and heat is easily generated,
If the temperature reaches the operating temperature range after heat generation, the resistance increases with the temperature rise.
Rises and controls the current to generate heat (I^Two・ R)
PTC song as shown in Fig. 1
What draws a line is a good heating element. In other words, small at normal temperature
Indicates the electrical resistance (small volume resistivity), and
The rate of increase in resistance to temperature rise is large (PTC coefficient is large
I) The composition is a heating element with better temperature controllability
You. (Calculation of PTC coefficient) Heating element resistance (Ω) at room temperature (20 ° C.): R₂₀ Resistance value (Ω) at a heating element surface temperature of 100 ° C .: R
₁₀₀ PTC coefficient = (R₁₀₀-R₂₀) / (100-20) The higher the PTC coefficient value, the more accurate the exothermic temperature control
Will be higher. PTC from the viewpoint of heat generation temperature control
The coefficient is preferably 2.0 or more, particularly preferably 2.3 or more.
No. (2) Volume resistivity The volume resistivity at room temperature (20 ° C.) was measured. Volume specific
The size of the resistor is SRIS2301-1969 Wheat
It was measured by the Stonebridge method. (3) Formability Based on JIS K7210 (230 ° C, 5kg load)
MFR was measured. (4) Mechanical strength Tensile in tensile strength and elongation test (based on JIS 7113)
The elongation at break and the tensile strength at break were measured. Examples 2 to 7 Each component shown in Table 1 was blended.
The prepared composition was prepared and evaluated in the same manner as in Example 1.
Table 1 shows the results. [0037] [Table 1]Comparative Examples 1 to 12
A combined composition was prepared and evaluated as in Example 1 above.
Was. Table 2 shows the results. [0039] [Table 2][0040] [Table 3] [0041] As described above, according to the present invention, heat is generated.
Excellent temperature control, mechanical strength and moldability
A conductive resin composition is obtained. Especially, olefin resin
Easy to extrude to make rod or linear
Can be processed into various shapes such as
Or, it is useful as a material for exothermic molded
It is also economically superior.

[Brief description of the drawings] FIG. 1 is a correlation curve (PTC curve) between surface temperature and resistance.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI H01B1 / 24 H01B1 / 24Z (58) Field surveyed (Int.Cl. ⁷ , DB name) C08L 23/00-23 / 36 C08K 3/00-13/08 H01B 1/00 H01B 1/24

Claims (1)

(57) [Claim 1] A melt flow rate (MFR) of 3 to 80.
g / 10 minutes, 100 parts by weight of a propylene-based polymer (A) having an ethylene content of 1 to 10% by weight and an α-olefin having 4 to 12 carbon atoms of 0 to 10% by weight, and a density of 0.1%. 10 to 120 parts by weight of an ethylene polymer (B) having a melt flow rate (MFR) of 0.5 to 40 g / 10 min or more and an average particle diameter of 20 m / m or more and a BET specific surface area of 920 g / cm ³ or more and 0.5 to 40 g / 10 min. 500m ² / g
The above carbon black (C) and an average particle size of 5 to 40
μm of flaky graphite (D) is added in an amount of 10 to 50 parts by weight based on 100 parts by weight of the total of the components (A) and (B).
And olefin-based conductive resin composition characterized in that a total amount formed by 20 to 100 parts by weight.