JPS5816946B2 - Manufacturing method for resin-lined hollow tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION It is known to pour a mixture of liquid resin and glass flakes onto the inner surface of a steel tube, apply it under centrifugal force, and harden it to obtain a plastic-lined tube.

The coating layer (lining layer) obtained by this method has excellent corrosion resistance and liquid penetration resistance, but the coefficient of thermal expansion is still quite large compared to that of inorganic pipes such as steel pipes, so after resin coating. In practical terms, the problem of cracks in the lining layer and/or peeling of the lining layer from the tube base due to temperature changes due to heat hardening of the tube and subsequent cooling, or repeated temperature changes that the lined tube undergoes during use, has been solved. cannot be improved to a satisfactory level.

Furthermore, the glass flakes mixed in the resin have poor alkali resistance, making the resulting lined tube unsuitable for handling alkaline chemicals.

The present invention has solved this problem, and according to the present invention, a liquid resin is poured into a rotating inorganic hollow tube,
The resin is uniformly applied to the inner surface of the hollow tube by the action of centrifugal force, and when it is cured, mica flakes with a weight average aspect ratio of 30 or more are mixed with the five liquid resins to provide not only acid resistance but also resistance. It is possible to obtain a hollow tube 9 having a lining layer that is excellent in alkalinity and does not crack or peel off even under temperature changes during curing and repeated temperature changes.

The hollow tube to which the present invention is applied is an inorganic hollow tube 5 made of a metal such as iron, copper, steel, or aluminum, and a material using cement as a binder, such as cement concrete, cement mortar, or asbestos cement.

One of the advantages of the resin-lined hollow tube according to the present invention is that the coefficient of thermal expansion in the circumferential direction of the lining layer can be reduced to approximately the same value as that of the inorganic hollow tube, so that the temperature at which the resin cures No cracking or peeling of the lining layer occurs due to repeated temperature changes during use of the lining hollow tube.

When an attempt was made to improve the lining layer by using glass flakes instead of mica flakes, the centrifugal force caused the glass flakes to separate from the resin and settle.
It was found that the upper limit of the amount of flakes that can be applied uniformly under molding conditions that do not cause heat loss is about 22% in terms of volume fraction, but even in that case, the heat in the circumferential direction of the inning layer The expansion coefficient was significantly higher than that of the base material.

On the other hand, when using mica flakes, for example, when using flakes with a weight average aspect ratio of 60, the coefficient of thermal expansion in the circumferential direction of the lining layer should approximately match that of the steel pipe at a volume fraction of 10% in the resin. be able to.

This remarkable effect of mica flakes is due to the unique characteristic of mica flakes that the Young's modulus in the plane direction of mica flakes is more than 100 times higher than that of glass. It is highly dependent on being placed under power.

Mica flakes that can be used in the present invention include muscovite, 7
0 Gobite (Sugilite), Biotite, Lepi de.
Usual mica arm openings such as lite, margarite, sericite, and synthetic roloph rogovite are preferred, but phlogovite (for example, sugilite) is particularly preferred because it has excellent bonding properties with the resin.

In the present invention, the weight average aspect ratio of mica flakes is determined by the following formula.

Weight average aspect ratio - diameter of flake (D) / thickness of flake t) -D2M, +D2M2+...+DnM
n/J Ml +t2M2+...±tnMn, where is the average diameter of one mica flake, tl is the average thickness of the flake, and M represents the total weight of a group of flakes having the shape of , t.

D2. t2. M... Dn, tn, and Mn also have the same meaning.

In addition, the average flake diameter of each of D2...Dn is determined by the area of π(D/2)2=1 flake.

In order to improve the bonding state between the mica flakes and the resin, and to layer the mica flakes in parallel in the resin by centrifugation, to obtain a lining layer with a low coefficient of thermal expansion and excellent resistance to penetration of chemical solutions, mica flakes were used. The weight average aspect ratio of is required to be at least 30.

In the present invention, the aspect ratio of the mica flakes is preferably as high as possible, and those having an aspect ratio of 60 or more, particularly 90 or more are most preferably used.

Generally, mica flakes have a diameter (D) of 500 mesh to 1 c.
fn preferably 100 mesh to 0.5LZ771, thickness t) 0.1 to 40 microns, preferably 0.2 to 30
It is preferable to appropriately select from microns depending on the desired weight average aspect ratio.

In the present invention, the liquid resin can be a low molecular weight liquid thermoplastic resin, a high molecular weight thermoplastic resin dissolved in a solvent, and a thermoplastic polymer in the form of an emulsion or latex, but includes unsaturated polyester resins, epoxy resins, Thermosetting resins that are liquid at room temperature, such as furan resins, are preferably used.In particular, unsaturated polyester resins can be easily obtained with low viscosity, so they have good lining workability and are easy to control the curing reaction. It is preferable as a liquid resin to be used in the present invention because of its fast curing properties.

Mixing of the resin and mica is carried out by adding mica flakes to the liquid resin and uniformly dispersing the mixture while stirring, but at this time care must be taken not to destroy the shape of the mica flakes as much as possible.

Before mixing, treating the mica flakes with a coupling agent is effective in enhancing the bond between the resin and mica.

The type of coupling agent varies depending on the resin used, but organic silane coupling agents such as vinyl silanes such as vinyltriethoxysilane for unsaturated polyester resins, and gamma-aminopropyltriethoxysilane for epoxy resins, etc. Aminosilanes are common.

If the mica flakes have water of crystallization, it may be preferable to heat or bake them in advance to remove some or all of the water of crystallization, and then mix them with the resin.

The mixing ratio of mica flakes to the resin is 5 to 80% by weight, preferably 10 to 50% by weight, most preferably 20 to 50% by weight.
40 weight section.

Other fillers, such as glass flakes, can be used in combination, provided that the effectiveness of the mica flakes according to the invention is not significantly diminished.

As mentioned above, the liquid resin most preferably used in the present invention is an unsaturated polyester resin, but this resin has the disadvantage that the lining layer tends to peel or crack due to its large shrinkage upon curing. be.

Curing shrinkage of unsaturated polyester resins is caused by styrenic polymers such as polystyrene, random or block copolymers of styrene and conjugated diethyl (isoprene, butadiene, etc.), copolymers with other vinyl or vinylidene monomers, unsaturated This can be improved by adding 0.5 to 30 parts by weight per 100 parts by weight of the polyester resin.

However, when such low-shrinkage unsaturated polyester resins are applied to the lining of hollow tubes that are coated and cured under centrifugal force, they do not exhibit the desired low-shrinkage properties and other problems occur. I understand.

That is, since the styrene polymer, which is an anti-shrinkage agent, is transferred to the surface of the lining layer by centrifugal force, the effect of low shrinkage cannot be obtained, and the surface of the lining layer does not harden for a long time.

According to the present invention, by coexisting a comb-shaped copolymer (hereinafter sometimes referred to as a dispersion stabilizer) having a styrene polymer as a trunk and saturated polyester segments as branches in an unsaturated polyester resin, the shrinkage caused by centrifugal force is achieved. This prevents separation of the inhibitor, thereby solving the above problem, making use of the workability of the unsaturated polyester resin, and making it possible to fully exhibit the effects of adding mica flakes.

In the present invention, unsaturated polyester resins include unsaturated dibasic acids such as maleic anhydride, fumaric acid, and itaconic acid, polyhydric alcohols such as ethylene oxide, propylene glycol, butanediol, and hydrogenated bisphenol A, and phthalic acid and isophthalic acid. , terephthalic acid, endomethylenetetrahydrophthalic acid, tetrahuman convex phthalic acid, f(ET acid, succinic acid, adipic acid, trimellitic acid, and their acid anhydrides, etc.) by polycondensation as main components. It includes a known unsaturated polyester resin consisting of the obtained unsaturated polyester and a crosslinking monomer such as a monomer copolymerizable with the polyester, such as an alkenyl aromatic monomer, and an alkyl ester of acrylic acid and methacrylic acid.

The comb-shaped copolymer which is used as a dispersion stabilizer in the present invention and has a styrene polymer as a trunk and saturated polyester segments as branches is, for example, a comb-shaped copolymer having a saturated polyester having an unsaturated double bond at one end and an aromatic vinyl monomer. A method of copolymerization, a method of reacting a copolymer of maleic anhydride and an aromatic vinyl monomer with a saturated polyester having a hydroxyl group at one end, or a method of reacting a copolymer of a vinyl monomer with an epoxy group and an aromatic vinyl monomer. It can be produced by a method of reacting with a saturated polyester having a carboxyl group at one end.

The dispersion stabilizer is effective in an amount of 0.005 to 1.5 times the weight of the anti-shrinkage agent in the unsaturated polyester resin, preferably 0.02 to 0.8 times the amount by weight.

When lining the inner surface of a hollow tube with a mixture of mica flakes and liquid resin, the construction conditions (mixed amount of mica flakes and medium (rotational speed of the empty tube) is selected.

In the lining layer, the mica flakes are preferably stacked in as many layers as possible, and the amount of mica flakes mixed should be determined so that there are at least 10 layers, preferably 30 or more layers.

When using the above-mentioned low shrinkage unsaturated polyester resin, the thickness of the lining layer is approximately 0.2 to 10, or preferably 0.
．． 5 to 6 degrees is appropriate, and when using other liquid resins, 0
．． 2 to 5 shoes, preferably 0.5 to 371111, is suitable.

During lining, the base material may be treated with a primer to improve adhesion to the lining layer, or the lining layer may be top coated.

The lining layer obtained by the present invention has significantly improved cracking and peeling caused by repeated temperature changes, has excellent acid resistance and alkali resistance, and exhibits high resistance to penetration of chemical solutions. This will greatly expand the applications of inorganic hollow tubes such as cement concrete.

Next, the present invention will be explained in detail through examples.

Parts in the examples are parts by weight unless otherwise specified.

Example 1 Corrosion-resistant grade unsaturated polyester resin [■Kuraray,
100 parts of Claminac 6443), sugilite mica (
Weight average aspect ratio 60, particle size 40-70 mesh)
After mixing 30 parts, 0.5 part of a cobalt naphthenate (cobalt content: 6%) solution and 1.0 part of a 55% methyl ethyl ketone peroxide solution were sequentially added and mixed well.

The obtained composition 6 KP was divided into a diameter of 20071 m and a length of 3
QQ7#) While rotating a cylindrical split mold at a gravity magnification of about 30 times, the mixture was injected into the mold, and the rotation was continued at room temperature for 30 minutes.

After the rotation was stopped, it was further heated to 80° C. for 1 hour to complete the curing reaction.

The split mold for molding was cooled to room temperature to obtain a cylindrical molded product as a lining layer sample.

This molded product was placed in an electric heating chamber, and the temperature was varied in the range of 20°C to 60°C.The inner diameter of the molded product was measured at that time, and the linear expansion coefficient in the circumferential direction of the molded product was determined. 12 x 10', l/M°C.

The value of ko is the linear expansion coefficient of steel 15 x 10'7#!
/) #I! It is almost comparable to 'C.

Comparative example Glass flakes (particle size 1
Example 1 except that 30 parts (0 to 30 meshes) were used.
When the linear expansion coefficient in the circumferential direction of the molded product was measured under the same conditions as above, it was found to be 34xlO' in the temperature range from 20°C to 60°C.
The temperature was 7III1/°C.

Example 2゜Corrosion resistant grade unsaturated polyester resin [■ Made by Kuraray,
Claminac 6443) 100 parts sprite mica (weight average aspect ratio 60, particle size 40-70 mesh) 3
After mixing 0 parts, 0.5 parts of a cobalt naphthenate (6% cobalt content) solution and 1.0 parts of a 55% solution of methyl ethyl ketone peroxide were sequentially added and mixed well.

The obtained composition 6Ky was injected into a cylindrical steel pipe with a diameter of 1507'a and a length of 400 mm rotating at a speed of 5 in terms of gravity multiplier, and the rotation speed was accelerated to 50 in terms of gravity multiplier.
Rotation was continued for minutes at room temperature.

After the rotation was stopped, the tube was further heated to 80.degree. C. for 1 hour to obtain a steel tube whose inner surface was lined with an unsaturated polyester resin mixed with sprite mica.

No cracks were observed in the obtained lining layer, and the adhesion between the steel pipe and the lining layer was good.

The mica flakes were aligned parallel to the substrate.

Comparative Example 2 Glass flakes (particle size 1
When lining was performed under the same conditions as in Example 2 except that 30 parts (0 to 30 mesh) was used, some peeling occurred at the interface between the lining layer and the base material.

Comparative Example 3 Sprite mica (weight average aspect ratio 60, particle size 40
~70 mesh) instead of 30 parts sprite mica (weight average aspect ratio 10, particle size 100-170 mesh)
When lining was carried out under the same conditions as in Example 2 except for using 30 parts, peeling occurred at the interface between the lining layer and the base material, and the orientation of the sprite mica in the lining layer was very incomplete. there were.

Example 3゜ Shell chemical epoxy resin “828” for lining
100 parts of sprite mica (weight average aspect ratio 90)
, particle size 20-40 mesh) were mixed, 10 parts of diethylenetriamine was added as a hardening agent, and the mixture was diluted with 100 parts of thinner to obtain a lining composition.

1.3Kp of this composition was applied to the inner surface of a cement concrete pipe with an inner diameter of 140M and a length of 4001g1 rotating at a gravity multiplier of 3, and the rotation was continued for 30 minutes at room temperature.

After stopping the rotation, the lining surface was heated to 80°C for 1 hour.
The resin was post-cured.

The lining layer is in close contact with the cement concrete.
No abnormalities such as cracks or hair cranks were observed.

The mica flakes were aligned parallel to the substrate.

Comparative example Glass flakes (particle size 1
Lining was carried out under the same conditions as in Example 2, except that 40 parts (0-30 mesh, 2-3 μm thick) were used.

When the concrete layer was cooled to room temperature after completion of post-curing, some peeling occurred on the extreme surface of the concrete layer.

Example 4 Vinyl ester resin (manufactured by Showa Kobunshi ■, Lipoxy R-,
Sprite mica (weight average aspect ratio 90, particle size 20-40 mesh) surface-treated with vinyltriethoxysilane (camping agent) in a resin solution consisting of 100 parts of 800) and 10 parts of styrene (diluent). A lining composition was prepared by mixing 30 parts and 1.5 parts of benzoyl peroxide.

500 g of this composition was applied to the inner surface of a steel pipe with an inner diameter of 135 M and a length of 400 mm rotating at a gravity multiplier of 3, the rotation speed was accelerated to a gravity multiplier of 30, and the mixture was heated to 80°C. While doing so, the rotation was continued for 20 minutes.

The lining layer was in close contact with the steel pipe, and no abnormalities such as cracks or hair cranks were observed.

The mica flakes were oriented parallel to the substrate.

Comparative Example 5゜Instead of 30 parts of sprite mica surface-treated with vinyltriethoxysilane, 30 parts of glass flakes (particle size 10 to 30 mesh, thickness 2-3μ) surface-treated with vinyltriethoxysilane were used. When lining was performed under the same conditions as in Example 4 except for the above, some peeling occurred at the interface between the lining layer and the base material.

Example 5゜(1) Preparation of unsaturated polyester resin 2.0 mol of water, maleic acid, 4.0 mol of phthalic anhydride, 5.4 mol of propylene glycol, and 0.9 mol of diethylene glycol were added in a reaction vessel in a conventional manner. An esterification reaction was carried out by heating to 200° C. while passing a nitrogen gas stream, and an unsaturated polyester having an acid value of 45 was obtained.

45 parts of this unsaturated polyester was dissolved in 55 parts of styrene monomer, and 0.011 part of humanized quinone was mixed therein to obtain an unsaturated polyester resin.

(2) Preparation of styrene monomer solution of polystyrene Add polystyrene (Asahi Dow Industries ■) to 70 parts of styrene monomer.
A polystyrene solution was obtained by dissolving 30 parts of Styron 666) manufactured by Polystyrene Corporation.

(3) Production of dispersion stabilizer 1 mole of phthalic anhydride, 1 mole of succinic anhydride, and 2.1 moles of ethylene glycol were heated to 150°C under a nitrogen gas stream in a reaction vessel by a conventional method, and reacted for 2 hours to obtain Hafester. turned into a monster.

Thereafter, the mixture was heated to 200° C. to advance the esterification reaction, and a saturated polyester having a hydroxyl value of 17 was obtained.

The saturated polyester was cooled to 160°C and 0.07 mol of maleic anhydride was added.

Then dibutyl phthalate was added to saturated polyester 100
50 parts per part of the mixture were added, stirred thoroughly and dissolved, and after cooling to 80°C, 50 parts of styrene monomer was added to form a homogeneous solution.

Further, 1 part of benzoyl peroxide was added to carry out a radical copolymerization reaction at 80°C, and the polymerization was completed in 4 hours.

Comb-shaped with a polystyrene trunk and saturated polyester branches.

A copolymer was obtained.

(4) Lining of steel pipes After mixing 2.5 parts of the dispersion stabilizer (3) with 70 parts of the unsaturated polyester resin prepared in (1) above, 30 parts of the polystyrene solution (2) was added and the mixture was stirred and dispersed. Ta.

After mixing 30 parts of sugilite mica (weight average aspect ratio 60, particle size 40-70 mesh) with 100 parts of this resin liquid, 0.5 part of cobalt naphthenate (cobalt content 6%) solution and 55 parts of methyl ethyl ketone peroxide were added.
A lining composition was prepared by sequentially adding 1.0 part of % solution.

1.2 Kp of this composition was injected little by little into a cylindrical steel pipe with a diameter of 150 M and a length of 400 W11 rotating at a gravity multiplier of 5, and the rotation was continued at room temperature for 30 minutes.

After the rotation was stopped, it was cured at room temperature for 1 hour, and then heated to 80° C. for 1 hour to obtain a lined steel pipe.

The thickness of the lining layer was approximately 4.5 mm.

No cracks were observed in the obtained lining layer, and the adhesion between the steel pipe and the lining layer was good.

The mica flakes were parallel to the base material.

Example 6゜Three kinds of lining layer specimens obtained in Examples 2 to 4 were coated with a depth of 0.5 to 1. OM, 1 door width, 10-15 shoulder length with 5 notches on one side only, immersed in 10% caustic soda (containing a small amount of red ink) at 80°C for 10 days, and after 10 days hardness retention and weight change. The rates of each were investigated.

However, the weight change rate was measured by cutting out only the lining layer.

The results are shown in Table 1.

In addition, the permeability of alkali was examined, and there was no change in the notch portion in any of Examples 2 to 4.

On the other hand, in Comparative Examples 2 to 5, it was confirmed by the coloring of the ink that the alkaline liquid had penetrated through the glass flakes from the notch portion to the inside.

Claims (1)

[Scope of Claims] 1. A liquid resin is applied to the inner surface of an inorganic hollow tube under centrifugal force, and upon curing, mica flakes having a weight average aspect ratio of 30 or more are mixed with the liquid resin. A manufacturing method for resin-lined hollow tubes. 2 The liquid resin has (a) an unsaturated polyester, (b) a monomer copolymerizable with the unsaturated polyester, (C) a styrenic polymer, and (d) a styrenic polymer as a trunk, and has saturated polyester segments as branches. A method for producing a resin-lined hollow tube according to claim 1, which is made of a comb-shaped copolymer.