JPS6132743A - Multilayer structure pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention consists of a polypropylene resin layer containing glass fiber and an inorganic filler (hereinafter referred to as FRPP) as an intermediate layer, and a propylene-ethylene resin layer on the outside and inside. High strength multilayer structure sandwiched with polymer or polyethylene resin.
Concerning highly rigid and weldable glass fiber reinforced composite pipes.

Pipe made of polyolefin resin is generally used as a piping material for fluid transportation, but due to its excellent corrosion resistance, attempts are often made to use it as a structural material. in this case.

In order to obtain the strength and rigidity required for structural materials, attempts have been made to develop pipes made of polypropylene resin, propylene-ethylene copolymer, polyethylene resin, etc., which are blended with various reinforcing materials such as glass fiber. however,
The fiber-reinforced polyolefin resin pipes that have been developed in the past do not yet have sufficient rigidity and strength when used as structural materials, and it is difficult to weld the pipes together or the strength is insufficient. Met.

L Gloss Ω 1 Structures used in agriculture and fisheries are subject to severe corrosion from seawater, sunlight, etc., so steel materials are subject to significant wear and tear.They are coated with paint, polyethylene resin, vinyl chloride resin, etc., but the effect is cannot be said to be 1 minute. Particularly in the marine industry, corrosion caused by seawater is more severe than expected, and long-term lifespan cannot be guaranteed unless the steel is coated very carefully and sufficiently. FRP is also used in some parts, but the material is relatively expensive and the productivity is poor, so although it is good for items with irregular shapes, it is not suitable for items that need to be continuously produced. It is not necessarily a cheap material.

As a result of intensive research to develop a material with high rigidity and high strength using an inexpensive polyolefin resin as a base material, the inventor of the present invention has developed a highly rigid material made of polypropylene resin, unsaturated carboxylic acid-modified polypropylene resin, and inorganic filler. If glass fiber is added to this matrix as a reinforcing agent, a thermoplastic material with extremely high rigidity and high strength can be obtained. It was discovered that an inexpensive, high-rigidity, and high-strength laminated tube could be obtained by providing a layer containing a high concentration of glass #1lIa on the outer layer and a layer containing a high concentration of an inorganic filler on the inside, and developed the present invention. It was completed.

-'s and -'s ・na= The laminated pipe of the present invention is composed of at least three layers, and the first layer counting from the outside has the function of imparting weather resistance and a beautiful appearance. The second layer is a highly rigid layer made of a polypropylene resin containing glass fiber, an inorganic filler, and an unsaturated carboxylic acid-modified polyolefin, and more preferably has high tensile and bending strength due to a high concentration of glass #JIita. It is a multilayer structure consisting of an outer layer and an inner layer that has high rigidity due to a high concentration of inorganic filler. The innermost layer is made of a high molecular weight ethylene-propylene copolymer,
Preferably, the material has the function of maintaining the impact resistance of the laminated pipe.

To explain the present invention in more detail, the first layer counting from the outside preferably contains 0.5 to 2.5% by weight of carbon black in order to maintain weather resistance. The resin used is a polyethylene resin having an NFR of 0.05 to 2 g and 710 layers, a propylene-ethylene copolymer having an ethylene content of 5 to 20% by weight, or an arbitrary mixture of the two.

NFI? If it is less than 0.05 g/10 m1n, it becomes difficult to mold and it is difficult to obtain a sufficient appearance. Furthermore, if the MFR exceeds 2 g/1 h, especially in the case of polyethylene resin, the environmental stress cracking resistance etc. will be poor, making it undesirable for use. Considering moldability, appearance, physical properties, etc., MF
R is preferably 0.2 to 1.0 g/10 m1n.

Counting from the outside, the second layer is the part that exhibits strength and rigidity in the laminated pipe, and both layers may be constructed as one layer with a polypropylene resin matrix and an inorganic filler and glass fiber as a reinforcing material. Good, but preferably 2
The second layer on the outside has a high concentration of glass fiber and a low concentration of inorganic filler, and the third layer on the inside has a low concentration of glass fiber and a high concentration of inorganic filler. By doing so, the bending strength is improved by about 20 to 50% compared to simply forming the second and third layers with a powder having the same composition.

This is based on the principle that when bending stress is applied to a laminated pipe, stronger tensile stress is applied to the outer layers, so if the outer layers are strengthened, the bending strength will also be improved.

Regarding the composition of the compound constituting the second layer, the polypropylene resin that is the matrix has an MFR of 4 to 4.
80g/to+win(7) is good, preferably 8-20g/10m1n(7), MFR
When a polypropylene resin with a weight ratio of less than 4 g/10 m1n is filled with a high concentration of glass fiber or inorganic filler, the fluidity is significantly reduced, making molding difficult and causing poor appearance. Also, if the NFR exceeds 80 g/10 m1n, the melt viscosity is too low, making molding difficult.
It is also unfavorable in terms of strength.

As inorganic fillers, mica, talc, and other materials with a large spectral ratio of 7 are preferable in order to increase rigidity. Talc also serves as a crystal nucleating agent for polypropylene resin, and is cheaper than mica, so if the amount of filling is large, Talc is easier to use.

The average particle size of the inorganic filler ranges from about 1.5 to 10W, but smaller particle sizes are more effective in increasing rigidity, and an average particle size of 1.5 to 5JL is preferable. 0.1 to 30% by weight in the case of a multi-layer structure, 0.1 to 20% by weight in the outer layer, preferably 2 to 10% by weight.
It is. The inorganic filler is substantially integrated with the polypropylene resin and forms a matrix for the glass fibers.

When a polypropylene resin is filled with an inorganic filler, the rigidity increases with the amount of filling, but if the amount exceeds 20% by weight, the tensile strength decreases, which is not preferable. Also 0.1
If it is less than % by weight, there is little contribution to increasing rigidity.

When filling polypropylene resin with glass fiber and inorganic filler, if the total amount of filling exceeds 60% by weight, the material itself becomes brittle, which is undesirable, and glass fiber has a better effect on rigidity and strength than inorganic filler. It is much better, so if the total filling amount of both is 60%,
It is better to keep the amount of the inorganic filler within 10% by weight.

Glass fiber has a diameter of 9~12JL and a length of 3B~25I.
afil is used. The surface of the glass fiber is preferably treated with a silane compound to increase adhesion to the polypropylene resin matrix.

The filling amount of glass fiber is 30 to 50% by weight in a single layer, and 35 to 60% in the outer layer in a multilayer structure.
If the weight percentage is preferably 60 weight percent or more, not only can no improvement in rigidity, bending strength, or tensile strength be expected, but also extrusion molding itself becomes difficult.

Moreover, if it is less than 35% by weight, there is no point in dividing the glass fiber into two layers, one containing a large amount of glass fiber and the other containing a glass fiber containing a small amount.

Unsaturated carboxylic acid-modified polypropylene resin has the effect of not only improving the adhesion between glass fiber and polypropylene resin, but also increasing the affinity between the inorganic filler and polypropylene resin and improving impact resistance. ``If the amount added is 15% by weight or more, the effect will already reach a saturated state, and if it is less than 3% by weight, it can be said to be insufficient.Preferably, it is 5 to 10% by weight.Maleic anhydride is preferable as the unsaturated carboxylic acid. .

Further, the unsaturated carboxylic acid content is preferably in the range of 0.3 to 1.0% by weight.

The idea is to increase the rigidity of the inner layer as much as possible using an inorganic filler, which is cheaper than glass fiber, and to add glass fiber as an supplement. The inorganic filler used here has an average particle size of 4 to IO well,
The filling amount is 20-50% by weight. Full @ acid content is around 20%
If it is less than 50% by weight, sufficient rigidity cannot be obtained, and if it exceeds 50% by weight, moldability becomes poor. Preferably it is 30 to 40% by weight.

The glass fiber used has a fiber length of 3 to 25 mm, preferably 3 to 6 mm.

The amount of glass fiber filled is 10 to 30% by weight, preferably 15 to 20% by weight.

The unsaturated carboxylic acid-modified polypropylene resin is added in an amount of 3 to 15% by weight, preferably 5 to 10% by weight.

Polypropylene resin has MFR as well as the outer layer of multiple layers.
A material with an MFR of 4 to 80 g/710 min is used, but a material with an MFR of 8 to 20 g/10 ml is preferable.

The innermost layer is mainly for imparting impact strength and welding properties to the composite pipe, and is preferably a propylene-ethylene block copolymer having an ethylene content of 5 to 20% by weight, which has excellent impact resistance. When using a propylene-ethylene block copolymer having an ethylene content of 15 to 20% by weight, it is acceptable to mix and use ordinary polypropylene resin up to a maximum of 50% by weight.

The MFR of the propylene-ethylene block copolymer is 0.
05-2g/10mln, preferably 0.1-0
．． 83/iomin.

In order to supplement the rigidity of the entire laminated tube, 0.1 to 30% by weight of an inorganic filler with an average particle size of 2.5 to 10 μm is used in the innermost layer as well. If the filling amount of the inorganic filler exceeds 30% by weight, the welding properties and impact resistance will be insufficient. Moreover, if it is less than 0.1% by weight, its contribution to rigidity is insufficient.

When an inorganic filler is added to a propylene-ethylene block copolymer, adding 3 to 10% by weight of an unsaturated carboxylic acid-modified polypropylene resin at the same time increases the affinity between the inorganic filler and the propylene-ethylene block copolymer.
i! lii improves fl properties.

That is, by adding an inorganic filler and an unsaturated carboxylic acid modified polypropylene resin to a high molecular weight propylene-ethylene block copolymer, a pipe with relatively high rigidity and impact resistance can be obtained.

Further features of the glass fiber reinforced laminated pipe of the present invention include:
First of all, the bending elastic modulus of the tube is 5 to 7 times higher than that of a tube made of polypropylene resin alone, and the bending strength is 3 to 4 times higher.The polypropylene resin body lacks strength and rigidity and cannot be used as a structure. This makes it possible to expand into other fields.

In addition, it has extremely excellent weather resistance and corrosion resistance, so it can withstand long-term use.

Since the product can be manufactured by extrusion molding mainly using thermoplastic resin, productivity is extremely high and inexpensive materials can be supplied. Since the outermost and innermost layers are made of impact-resistant resin, it is strong against impact, and has both high rigidity and impact resistance. Furthermore, they are annoyed by the ability to freely join tubes together by welding.

Regarding the manufacturing method of the multilayer structure pipe, for example, in the case of a 4-layer laminated pipe, the general method is to use 4 extruders to extrude 4 types of resin compositions into a rotating part and mold it with a 4-layer pipe die. However, there is also a method of first forming the innermost pipe that will become the core pipe, and then sequentially laminating layers on top of it using a coating die.

If the amount of glass fiber added is large, sifting and unevenness will occur on the surface during the cooling and solidification process of the molten resin composition, so the latter method yields better results.

The resin composition is obtained by first thoroughly mixing the resin and the inorganic filler in a Henschel mixer, then transferring the mixture to a tumbler or ribbon mixer, adding glass fibers, and stirring and mixing.

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but it goes without saying that the scope of the present invention is not limited to these Examples.

The compound for the first layer (outermost layer) of "Jijutsu" is made from 2.5 parts by weight of carbon black and 87.5 parts by weight of a propylene-ethylene block copolymer with an MFR of 0.7 g/10 m1n and an ethylene content of 15ii%. Chopped strand glass fiber (C503 manufactured by Asahi Glass Fiber (special)) with a fiber length of 3III+ was used as a compound for the second layer.
- MA48BA) 50 parts by weight, 10 parts by weight of talc with an average particle size of 2.5 IL, maleic anhydride-modified polypropylene resin with a maleic anhydride content of 0.5% by weight (MI = 10 g/
10m1n) 10 parts by weight, MFR 8g/10m1
A composition consisting of 30 parts by weight of a polypropylene resin of n is used as a compound for the third layer, and chopped strand glass fibers (C9O3-M^488A
), 40 parts by weight of talc with an average particle size of 8 l, 5 parts by weight of a maleic anhydride-modified polypropylene resin, and 35 parts by weight of a polypropylene resin with an MFR of 83/IO min. ), as MFR
80 parts by weight of propylene-ethylene block copolymer of 0.7 g/10 m1n, talc with an average particle size of 2.5 5
A composition consisting of 5 parts by weight of the maleic anhydride-modified polypropylene resin described above was first extruded at a temperature of 230°C from an extruder with an innermost layer of 50 am to form a resin composition with an outer diameter of 35 mm.
A pipe with a wall thickness of 2II11 mm was molded. Next, the third layer was coated with a wall thickness of 2 mm on the 35I 1 ml pipe using a cross rad die, and then the second layer was coated with a wall thickness of 2+e.
Finally, the first layer was coated with a wall thickness of 0.81 mm to produce a 4-layer laminated tube.

When a load was applied to this composite pipe at a midpoint with a span interval of 2 m and the bending strength was measured, the breaking load was 180 kg.

The results of measuring other physical properties of the composite pipe were as follows: bending elastic modulus: 10 (j, 000 kgf/crn'), tensile strength: 1.5
00 kgf/crn'・Also, for this laminated pipe at room temperature 100 kgrn'/5
I added ec2's 1711 energy, but it did not destroy it.

2-4 and 1-4 Four-layer laminated pipes were manufactured using resin compositions having the formulations shown in Table 1 in the same manner as in Example 1, and their physical properties were measured.

The results were as shown in Table 1.

The composition of the outermost layer and the innermost layer counting from the outside is as in Example 1.
is the same as

Claims (1)

[Scope of Claims] 1. A polyolefin multilayer structure tube consisting of at least three layers, characterized in that it has a polypropylene resin layer containing glass fiber, an inorganic filler, and an unsaturated carboxylic acid-modified polyolefin as an intermediate layer. 2. The polypropylene resin layer is made of glass fiber 35-60
% by weight, outer layer with 0.1-20% by weight of inorganic filler and 10-30% by weight of glass fiber, 20-50% by weight of inorganic filler.
% by weight of the inner layer.