JP2000095886A - Resin molded product having surfactant film, its production, and prevention of deterioration of resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for suppressing the deterioration, by a metal ion, of a resin molded product. SOLUTION: The deterioration, by a metal ion, of a resin molded product can be suppressed by preventing the contact of the resin molded product with the metal ion by forming a single layer of a surfactant on the surface of the resin molded product which comes into contact with the metal ion. The resin molded product on which a surfactant film was formed can be produced by attaching an surfactant on the surface of the resin molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin molded article having a surfactant film formed thereon, a method for producing the same, and a method for preventing deterioration of the resin molded article.

[0002]

2. Description of the Related Art In recent years, thermoplastic resin pipes have been introduced as water supply pipes or hot water supply pipes. Known thermoplastic resin tubes include, for example, cross-linked polyethylene tubes, polyethylene tubes, polybutene tubes, polyvinyl chloride tubes, and the like.

[0003] These thermoplastic resin tubes are being replaced with conventional metal tubes because of their excellent properties such as flexibility, light weight, and corrosion resistance. For example, water introduced from a metal water supply pipe buried in a road into the premises as a branch and supplied to the heat source unit by the metal pipe is transported from the heat source unit to each room via a thermoplastic resin pipe. May be.

[0004] Thermoplastic resin pipes are used not only for transient water piping such as bathrooms, kitchens, sinks, etc., but also for floor heating, fan control vectors, air conditioners, etc. utilizing the circulation of hot water. .

[0005] In these pipes, in addition to the cold / hot water itself,
Metal ions generated from the metal tube and the metal part of the heat exchanger in the heat source device are flowing. Such metal ions are mainly iron ions (Fe ²⁺ ) and copper ions (Cu ²⁺ ). While flowing through the pipe, these metal ions directly degrade the thermoplastic resin pipe from the inner surface or react indirectly with the metal deactivator in the antifreeze liquid added to the cold and hot water. Thus, an unnecessary chelate compound is formed, and the chelate compound migrates into the inside of the thermoplastic resin tube, thereby deteriorating the tube. In particular, in a circulating water piping, the above tendency is remarkable because the metal ion concentration increases with time.

[0006]

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to prevent a resin molded product such as a thermoplastic resin from being deteriorated by a metal ion or a chelate compound.

[0007]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, when the surface of a resin molded product is coated with a surfactant, metal ions are formed on the resin surface. Direct contact can be prevented, and the chelate compound produced by the reaction between the metal ion and the metal deactivator in the antifreeze can be prevented from migrating into the resin tube, thereby significantly deteriorating the resin molded product. Has found something that can be prevented. The present invention has been completed based on such findings.

According to the present invention, there is provided a resin molded article having a single layer film formed of a surfactant.

According to the present invention, there is provided a resin molded product in which a monolayer film of a surfactant is formed and the surface layer of the molded product is impregnated with the surfactant.

Further, according to the present invention, a surfactant is formed on the surface of a resin molded product, and a monolayer film of the surfactant is formed on the surface of the molded product. The present invention provides a method for producing a molded resin article.

Further, according to the present invention, a monolayer film of a surfactant is formed on the surface of a resin molded product which comes into contact with a metal ion and a chelate compound produced by a reaction between the metal ion and a metal deactivator in an antifreeze. The present invention provides a method for preventing a metal ion or a chelate compound from coming into contact with a resin molded product and suppressing deterioration of the resin molded product due to the metal ion or the chelate compound.

In the resin molded product coated with the surfactant of the present invention, the metal ions do not come into direct contact with the resin surface, and the chelate formed by the reaction between the metal ions and the metal deactivator in the antifreeze solution. Since the compound does not migrate into the inside of the resin molded product, deterioration of the resin molded product is significantly suppressed, and the resin molded product can be used for a long period of time.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the resin constituting the resin molded product is not particularly limited, and conventionally known thermoplastic resins and thermosetting resins can be widely used. Examples of the thermoplastic resin include crosslinked polyethylene, polyethylene, polybutene, polyvinyl chloride and the like. Further, as the thermosetting resin, for example, polyamide,
ABS resin and the like can be mentioned. Among these,
Particularly, crosslinked polyethylene is preferable. In the present invention, the shape of the resin molded product is not particularly limited, and examples thereof include a tubular shape, a tubular shape, and a plate shape.

The resin molded product of the present invention has a monolayer film formed of a surfactant on the surface thereof. Here, the surface means a surface that comes into contact with water containing metal ions when the resin molded product is used. Therefore, when the resin molded product is tubular or tubular, the surface means the inner surface of the tubular or tubular resin molded product.

In the resin molded product of the present invention, the surface layer of the resin molded product may be impregnated with a surfactant. Here, the surface layer of the resin molded product is a surface of the resin molded product and a portion in the vicinity thereof, and is usually several tens nm to several tens μm from the surface of the molded product.
It refers to a part that has entered the interior by about m.

The surfactant is not particularly limited, and conventionally known cationic surfactants, anionic surfactants, amphoteric surfactants, nonionic surfactants and the like can be widely used. Among these various surfactants, for example, general formula (1) AB (1) wherein A is an aromatic hydrocarbon group having an aliphatic hydrocarbon group or a side chain aliphatic hydrocarbon group or an alicyclic group Shows a hydrocarbon group. B represents a hydrophilic group. ] Is preferable.

In the above general formula (1), the aliphatic hydrocarbon group represented by A may have one or several unsaturated bonds such as a double bond and a triple bond in the hydrocarbon group. Good. The aliphatic hydrocarbon group may be linear or branched, but is preferably a linear one. Also,
Some or all of the hydrogen atoms in the aliphatic hydrocarbon group may be replaced by another element, for example, a fluorine atom. Further, the aliphatic hydrocarbon group is preferably composed of 10 or more carbon atoms, preferably 12 to 16 carbon atoms.

Specific examples of such aliphatic hydrocarbon groups include n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl and n-decyl. A hexadecyl group and the like can be exemplified.

In the general formula (1), examples of the aromatic hydrocarbon group represented by A include a phenyl group and a naphthyl group. As the alicyclic hydrocarbon group, for example, a cyclopentyl group, a cyclohexyl group,
5-8 carbon atoms such as a cycloheptyl group and a cyclooctyl group
Can be mentioned.

The side chains of these aromatic hydrocarbon groups and alicyclic hydrocarbon groups have aliphatic hydrocarbon groups. The side chain aliphatic hydrocarbon group may contain one to several unsaturated bonds such as a double bond and a triple bond in the hydrocarbon group.
The aliphatic hydrocarbon group may be linear or branched, but is preferably a linear one. In addition, some or all of the hydrogen atoms in the aliphatic hydrocarbon group is another element,
For example, it may be substituted by a fluorine atom or the like. Further, the aliphatic hydrocarbon group preferably has 1 to 18 carbon atoms, particularly preferably 10 to 16 carbon atoms. Specific examples of such an aliphatic hydrocarbon group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group. , N-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group and the like.

In the general formula (1), the hydrophilic group represented by B is mainly composed of an ionic group as a main component, for example, a sulfonic group (—SO ₃ H), a carboxyl group (—COOH). ), phosphoric acid group (-H ₂ PO _4), or the like, or salts (e.g., sulfonates (-OSO ₃ M), carboxylates (-COOM), phosphate (-H ₂ PO ₃ (OM),
—H ₂ PO ₂ (OM) ₂ ) and the like. Here, M is preferably an alkali metal salt or the like.

Specific examples of the anionic surfactant represented by the above general formula (1) include sodium laurate, potassium laurate, sodium myristate, potassium myristate, sodium barmitate, potassium barmitate, and stearin. Fatty acid soap having 10 to 18 carbon atoms, such as sodium silicate, potassium stearate, sodium oleate, potassium oleate, 4- (n-dodecyl)
Examples thereof include sodium alkylbenzenesulfonate such as sodium benzenesulfonate, sodium alkylnaphthalenesulfonate, alkyl ether phosphate, alkyl phosphate, sodium 4- (n-heptyl) cyclohexylcarboxylate and the like. Among them, sodium laurate, sodium 4- (n-dodecyl) benzenesulfonate, sodium 4- (n-heptyl) cyclohexylcarboxylate and the like are preferable.

Further, in the present invention, a quaternary ammonium salt,
Cationic surfactants such as pyridinium salts and non-ionic surfactants such as polyoxyethylene glycols and polyhydric alcohols can also be used. Specific examples of the cationic surfactant include benzyltri-n-butylammonium chloride, benzyldimethylstearylammonium chloride, and hexadecylpyridinium chloride.
Specific examples of the nonionic surfactant include hexamethylene glycol dodecyl ether, polyoxyethylene octyl phenyl ether, sucrose monolaurate, and sorbitan monolaurate.

In the present invention, a monolayer film of one or more of the above surfactants is formed on the surface of the resin molded product.

There is no particular limitation on the formation of a single-layer film of a surfactant on the surface of the resin molded product, and conventionally known methods can be widely applied.

As a typical method, for example, a method in which a surfactant is adsorbed on the surface of a resin molded product, and a monolayer film formed of the surfactant is formed on the surface of the molded product can be cited.

More specifically, the resin molded product may be immersed in a surfactant solution to form a monolayer film of the surfactant on the surface of the molded product.

When the resin molded product is tubular,
What is necessary is just to circulate the surfactant solution inside the tubular resin molded product and form a single-layer film of the surfactant on the inner surface of the molded product.

As the surfactant solution, an aqueous solution of a surfactant is usually used. The concentration of the surfactant in the aqueous solution is not particularly limited, and may be an amount sufficient to cause the surfactant to be adsorbed on the surface of the resin molded product by the above method and form a film of the surfactant on the surface of the molded product. It is 1 to 30% by weight, preferably 5 to 15% by weight.

After the formation of the surfactant film on the surface of the molded article, the resin molded article is subjected to a drying treatment as required. As the drying treatment method, conventionally known methods can be widely used, and examples thereof include a natural drying method, a heating drying method, and a vacuum drying method.

A resin molded product having a monolayer film formed of a surfactant on the surface of the molded product is used, for example, as a resin pipe such as a water supply pipe or a hot water supply pipe. The usage may be the same as the conventional usage.

[0032]

According to the present invention, a monolayer film made of a surfactant is formed on the surface of a resin molded product which comes into contact with metal ions by the above-mentioned various methods, and the contact of the resin molded product with metal ions or the like can be prevented. This can prevent the resin molded product from deteriorating due to metal ions and the like. Therefore, according to the present invention, the reliability of a piping system using a resin pipe can be improved.

[0033]

The present invention will be further clarified with reference to the following examples.

Example 1 As a thermoplastic resin pipe, a crosslinked polyethylene pipe (heating pipe,
Mitsubishi Chemical Industrial Co., Ltd. product, 10A, length 1 cm) was used.

The following surfactants were used.

Surfactant A: Sodium laurate Surfactant B: Sodium 4- (n-dodecyl) benzenesulfonate Surfactant C: Sodium 4- (n-heptyl) cyclohexylcarboxylate % Of an aqueous solution prepared by immersing the crosslinked polyethylene tube at a temperature of 60 ° C. for 1 week, and then saturating copper sulfate (CuSO ₄ ) (Showabrine PP Regular, Showa Corp.)
Was immersed at a temperature of 60 ° C. for 4 weeks. Next, the crosslinked polyethylene tube was taken out, and the tube surface was subjected to infrared absorption analysis and T
OF-SIMS (Time Of Fright-Secondary Ion Mass
Spectrum, a time-of-flight secondary ion mass spectrometer). Copper sulfate was used as a source of copper ions present in the water.

For comparison, the above crosslinked polyethylene tube was immersed in water at 60 ° C. for one week, and then copper sulfate (CuS
O ₄ ) The sample was immersed in a saturated antifreeze solution at a temperature of 60 ° C. for 4 weeks, then the crosslinked polyethylene tube was taken out, and the surface of the tube was subjected to infrared absorption analysis.

FIG. 1 shows an infrared absorption spectrum of the surface of the crosslinked polyethylene tube not treated with the surfactant. In addition, FIG. 2 shows an infrared absorption analysis diagram of the surface of the crosslinked polyethylene tube treated with the surfactant A, and FIG. 3 shows an infrared absorption analysis diagram of the surface of the crosslinked polyethylene tube treated with the surfactant B. FIG. 4 shows infrared absorption analysis diagrams of the surface of the crosslinked polyethylene tube treated with the surfactant C.

The following can be seen from FIG. That is, the copper ions emitted from the copper sulfate combine with the copper harm inhibitor in the antifreeze to form a copper chelate compound. In FIG. 1, the peak due to the copper chelate compound was observed at 1000 to 1700 cm ^-1 . In other words, in a system where no surfactant is added,
The copper chelate compound migrated into the inside of the crosslinked polyethylene tube.

On the other hand, in the system to which the surfactants A, B or C were added, as apparent from FIGS. 2, 3 and 4, no peak due to the copper chelate compound was observed at 1000 to 1700 cm ^-1. I couldn't. This indicates that the copper chelate compound has not migrated into the inside of the crosslinked polyethylene tube.

From the results of TOF-SIMS analysis of the surface of the crosslinked polyethylene tube treated with surfactant A, B or C, the molecular ion peak of each surfactant was confirmed on the surface of each crosslinked polyethylene tube. From that
It was confirmed that a monolayer film of a surfactant was formed on the surface of the crosslinked polyethylene tube.

From the above results, by forming a single-layer film of a surfactant on the surface of the thermoplastic resin molded product,
It can be seen that the copper chelate compound can be prevented from migrating into the thermoplastic resin molded product.

Example 2 The same thermoplastic resin tube, surfactant and antifreeze as in Example 1 were used.

In the same manner as in Example 1, 10% by weight aqueous solutions of various surfactants were prepared, and the above-mentioned crosslinked polyethylene tube was immersed at a temperature of 60 ° C. for one week.
It was immersed in an antifreeze saturated with uSO ₄ ) at a temperature of 60 ° C. for 6 months. Next, the crosslinked polyethylene tube was taken out, and the tube surface was observed. As a result, no change was recognized on the tube surface.

For comparison, a crosslinked polyethylene tube was used for 60
After immersion in water at 60 ° C. for 1 week, it was immersed in a saturated antifreeze solution of copper sulfate (CuSO ₄ ) at a temperature of 60 ° C. for 6 months, and then the crosslinked polyethylene tube was taken out and the tube surface was observed. As a result, changes such as cracks were observed on the tube surface, and deformation such as swelling was observed on the tube itself.

[Brief description of the drawings]

FIG. 1 is an infrared absorption diagram of the surface of a crosslinked polyethylene tube that has not been treated with a surfactant.

FIG. 2 is an infrared absorption analysis diagram of the surface of a cross-linked polyethylene tube treated with surfactant A.

FIG. 3 is an infrared absorption diagram of the surface of a crosslinked polyethylene tube treated with surfactant B.

FIG. 4 is an infrared absorption diagram of the surface of a crosslinked polyethylene tube treated with surfactant C.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromichi Inoue 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka Gas Co., Ltd. (reference) 4F006 AA12 AA17 AA22 AA38 AB69 BA00 CA00 DA00 DA04

Claims (9)

[Claims] 1. A resin molded article having a monolayer film formed of a surfactant on the surface of the molded article. 2. The resin molded article according to claim 1, wherein the surface layer of the resin molded article is impregnated with a surfactant. 3. The method according to claim 1, wherein the surfactant has the general formula AB
Represents an aromatic hydrocarbon group or an aromatic hydrocarbon group having a side chain aliphatic hydrocarbon group or an alicyclic hydrocarbon group. B
Represents a hydrophilic group. And a compound represented by the formula:
Or the resin molded product according to claim 2. 4. The molded article according to claim 1, wherein the molded article is tubular.
Or the resin molded product according to claim 3. 5. A resin molding on which a single-layer film of a surfactant is formed by adhering a surfactant to the surface of the resin-molded product and forming a single-layer film of the surfactant on the surface of the molded product. Method of manufacturing a product. 6. The method for producing a resin molded product according to claim 5, wherein the resin molded product is immersed in a surfactant solution to form a monolayer film of the surfactant on the surface of the molded product. 7. The method for producing a resin molded product according to claim 5, wherein a surfactant solution is circulated inside the tubular resin molded product, and a monolayer film of the surfactant is formed on the inner surface of the molded product. . 8. The surfactant represented by the general formula AB
Represents an aliphatic hydrocarbon group or an aromatic hydrocarbon group or an alicyclic hydrocarbon group having an aliphatic hydrocarbon group in a side chain.
B represents a hydrophilic group. The method for producing a resin molded product according to claim 5, which is a compound represented by the formula: 9. Forming a monolayer film of a surfactant on the surface of a resin molded product that comes into contact with a metal ion or a chelate compound to prevent the metal ion or the chelate compound from coming into contact with the resin molded product. A method for preventing a product from being deteriorated by a metal ion or a chelate compound.