JPS62194041A - Spring covered by synthetic resin - Google Patents

Abstract

PURPOSE:To improve sound deadening property, durability, and corrosion resistance, by covering the surface of a spring with denatured olefin copolymer denatured by unsaturated carboxylic acid or its derivative through sermosetting resin. CONSTITUTION:A spring comprise a cylindrical spring or a leaf spring. Thermosetting resin is made of epoxy, melamine, phenol resin, or the like. the surface of the spring is covered by the sermosetting resin first and then it is covered by denatured olefin copolymer such as polyethylene, polypropylene or the like and its outside is covered by the same or different kind of thermosetting resin or rubber as necessary. The spring thus constructed is excellent in sound deadening property as well as in durability and corrosion resistance since it is bonded to the covering film strongly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a synthetic resin-coated spring with excellent noise-damping effect and corrosion resistance.

[Prior Art] Springs have conventionally been widely used as industrial parts in automobiles, vehicles, and the like. One of these is a coil spring, which is used as a suspension device between a car's axle and the car body, and serves as a cushion between the center axle and the car body.
It is responsible for important structural parts. These coil springs have a problem in that they collide with each other due to imaging, impact, etc. that occur when the vehicle is running, producing a banging sound and noise.

Further, there are other problems, such as rusting and corrosion due to moisture and stone debris solutions (for example, road surface anti-icing agents), and the risk of breaking accidents due to corrosion fatigue.

In order to solve these problems, coil springs are wound with polyurethane sheets or rubber or resin duplexes are used, but the adhesion to the coil springs is not sufficient. Intrusion of moisture etc. cannot be effectively prevented. On the other hand, there is a method of coating a coil spring with resin (for example,
-69'123, No. 57-136971, etc.), using adhesives or sealants, etc., but they have poor durability and are not sufficient under severe conditions where repeated stress is applied. I can't expect any good results.

[Problem to be Solved by the Invention 1] The present invention has been made as a result of intensive studies in view of the above points, and the purpose of the present invention is to prevent collisions between springs when a car is running, etc. It has excellent sound-dampening properties to prevent noise caused by springs, and the adhesive strength between the spring and the coating film is high, so the coating film can be used even under harsh conditions where repeated stress is applied, such as in automobile suspension systems. The object of the present invention is to provide a synthetic resin-coated spring that has durability without cracking, is strong against damage caused by chipping (depping resistance), and has remarkable effects on corrosion resistance, especially salt water resistance.

[Means for Solving the Problems] The present invention provides a modified olefin polymer modified with an unsaturated carboxylic acid or a derivative thereof with a thermosetting resin interposed on the surface of a spring, or a modified olefin polymer modified with an unsaturated carboxylic acid or a derivative thereof with a thermosetting resin interposed therebetween. The present invention provides a synthetic resin-coated spring characterized by being coated with a composition containing a modified olefin polymer.

The spring of the present invention includes cylindrical or conical coil springs, torsion springs, bar torsion springs, spiral springs, flat springs, stacked leaf springs, torsion bars, ring springs, etc. This has a remarkable effect on coil springs used under harsh conditions such as when driving, where stress is applied.

Thermosetting resins used in the present invention include epoxy resins, melamine resins, unsaturated polyester resins, urethane resins, alkyd resins, thermosetting acrylic resins, phenolic resins, etc. alone or in combination of two or more. Examples include thermosetting resins consisting of combinations, and among these, in particular, phenolic resin-epoxy resin paints, urea resin-epoxy resin paints, melamine resin-epoxy resin paints, amino-alkyd resin paints, and melamine resin-alkyd resin paints. , polyurethane resin paint, phenolic resin - epoxy resin -
Vinyl resin paints or adhesives made of these resins are preferred. Further, a curing agent may be added as appropriate.

If the film thickness of the thermosetting resin is about 5 to 50 μm, it is sufficient to impart corrosion resistance (salt water resistance), but it may be even thicker. The thermosetting resin film can be formed by applying the above-mentioned paint or adhesive, such as a solvent type, dispersion type, or non-solvent type, by a well-known method.

The olefin polymers used in the present invention, modified or unmodified, include olefin polymers such as polyethylene, polypropylene, polybutene-1, poly 4-methylpentene-1, ethylene, propylene-1, etc.
．． Butene-1,4-methylpentene-1, hexene-1
, mutual copolymers such as octene-1, copolymers of ethylene and vinyl esters such as ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ■ dylene-acrylic acid copolymers: ethylene-glycidyl methacrylate A copolymer of ethylene and an unsaturated carboxylic acid, an unsaturated carboxylic acid ester, etc., such as a copolymer and an ethylene-malein ll[li polymer, can be used. especially,
Among these, the density is 0.86 to 0.94 (1/cd
Copolymers of ethylene and α-olefins having 3 to 12 carbon atoms (commonly called linear low-density polyethylene), ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers Ethylene comonomers such as coalesces or mixtures thereof are preferred.

The melt index of the above olefin polymer is 0.01 to 50 (1/10 min, preferably 0.1
~20 (selected in the range of 1/10 minute).

The unsaturated carboxylic acids used in the present invention include monobasic acids and dibasic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, and citraconic acid.

Further, examples of derivatives of unsaturated carboxylic acids include gold am, amide, imide, ester, anhydride, etc. of the above-mentioned unsaturated carboxylic acids, and among these, maleic anhydride is most preferred.

Unsaturated carboxylic acid or its derivative used in the present invention (
Hereinafter, an olefin polymer modified with an unsaturated carboxylic acid (abbreviated as V) in A) refers to an olefin polymer modified with an unsaturated carboxylic acid (abbreviated to V) as an olefin polymer containing 05 to 10% by weight of unsaturated carboxylic acid, preferably 0.
1 to 5.0% of heavy equipment is added and modified in the presence of organic peroxide.

The amount of the unsaturated carboxylic acid added is 0.05 fflfi
If it is less than 10% by weight, the adhesion will be poor, and if it exceeds 10% by weight, gel will occur, and the mW property will be reduced and the surface condition of the coating will deteriorate.

The above reaction can be carried out by melt-mixing in an extruder or mixer such as a Banbury mixer without a solvent, or using aromatic hydrocarbons such as benzene, xylene, toluene, aliphatic hydrocarbons such as hexane, heptane, octane, etc. The method of heating and mixing in a solvent such as a hydrocarbon and reacting is not particularly limited, but it is preferably carried out in an extruder because it is easy to operate and is economical.

When the amount of unsaturated carboxylic acid exceeds 10% by weight, decomposition and crosslinking reactions may occur in addition to addition reactions, and when it is less than 11% of 0.05 ff, the effects of the present invention cannot be achieved.

Examples of the organic peroxides include benzoyl peroxide, lauryl peroxide, azobisisobutyronitrile, dicumyl peroxide, t-butyl hydroperoxide, α,α'-bis((-butylperoxydiisopropyl)) Benzene, di[-butylperoxide, 2,5-di(t-butylperoxy)hexyne, etc.] are preferably used, and the olefin polymer is
It is used in a range of 0.01 to 260 parts by weight, preferably 0.01 to 151 parts by weight per part of mff. If the amount of organic peroxide added is less than 0 or 0 weight parts, the modification effect will not be substantially exhibited, and even if it is added in excess of 2 or 0 weight parts, it will be difficult to obtain any further effect. At the same time, there is a risk that excessive decomposition or crosslinking reaction may occur.

The above reaction temperature is appropriately selected in consideration of the usual temperature conditions, namely the deterioration of the resin, the decomposition of the unsaturated carboxylic acid, and the decomposition temperature of the organic peroxide.
Reaction temperatures in the range of °C are used.

The method for producing the above-mentioned modified olefin polymer can be either a method in which unmodified different types of olefin polymers are appropriately mixed in advance and then modified, or a method in which different types of modified olefin polymers are appropriately mixed. Alternatively, it is also possible to use a composition in which the modified olefin polymer is further mixed with an unmodified olefin polymer of a different type or the same type as appropriate. The mixing ratio of the modified olefin polymer and unmodified olefin polymer is arbitrary. (Hereinafter, the modified olefin carrier or the modified olefin polymer and unmodified olefin polymer composition will be simply referred to as a modified olefin polymer). Synthetic rubbers such as ethylene-propylene-diene rubber, styrene-butadiene rubber, polybutadiene rubber, chloroprene rubber, urethane rubber, ethylene-vinyl acetate monomer rubber, solid rubber such as natural rubber, or liquid rubber such as liquid polybutadiene. , natural rubber, and mixtures thereof modified or unmodified with unsaturated carboxylic acids or derivatives thereof may be used in combination with the modified olefin polymer. These rubbers contribute to improved sound deadening and bone contact.

The means for blending each component in J3 of the present invention is not particularly limited, and common mixing machines such as a ribbon blender, high-speed mixer, kneader, mixing roll, Banbury mixer 1 extruder, etc. can be used.

In the present invention, especially when emphasis is placed on sound deadening properties and durability such as coil springs, Eblene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, density 0.86 to 0.91 (1/cIl The main component is an ethylene copolymer such as an ethylene-brobylene copolymer, an ethylene-α-olefin copolymer such as an ethylene-butene-1 copolymer, and polyethylene other than the above,
Olefin homopolymers such as polypropylene, polybutene-1, poly-4-methylpentene-1, and olefins such as mutual copolymers of ethylene, propylene, butene-1,4-methylpentene-1, hexylene-1, octene-1, etc. Preference is given to using mixtures with polymers.

The modified ethylene copolymer contributes particularly to improved adhesion and sound deadening, while the latter olefin polymer contributes to durability and adhesion.

By appropriately mixing and coating the two, sound-dampening properties, adhesion, and durability are improved in a well-balanced manner, and strong adhesion provides excellent corrosion resistance, which is preferable.

The mixing ratio of the above-mentioned ethylene copolymer and the latter olefin polymer may be suitably mixed in the range of 100 to 50:0 to 50, and it is sufficient that one of the components is modified.

The i-layer on the surface of the spring is first coated with a thermosetting resin, then with a modified olefin polymer, and if necessary, the outer layer may be further coated with the same or different type of thermoplastic resin or rubber. .

When coating the spring with the thermosetting resin, it is sufficient if the surface of the spring is clean, but it is more effective to apply plasting or chemical conversion treatment.

Since the thermosetting resin is cured by heating, there is a method in which the thermosetting resin is heated and cured immediately after being subjected to N, and then coated with a modified olefin polymer in a subsequent step, or the modified olefin polymer is coated. There are no particular limitations on the method of curing at the same time as heating. The following methods for coating modified olefin polymers include: spirally winding and fusing a film or sheet of modified olefin polymer, extrusion coating of a modified olefin polymer, and coating with a sol of modified olefin polymer. Although a coating method or a method of extrusion coating or coating the modified olefin m compound by dissolving it in a solvent is possible, it is preferable to powder it and apply FW-Sj on the surface of the spring.

By powderizing in this way, the curvature of the spring is uniform,
Moreover, a strongly adhered coating layer can be formed.

Powderization can be carried out by a conventional method, and specifically, any method such as a mechanical pulverization method or a dissolution precipitation method may be used. The particle size of the powder is 50 to 350 μm, preferably 7 μm in order to form a uniform and strongly adhesive coating layer.
It is preferably in the range of 0 to 300μ.

Examples of coating methods using the powder include powder coating methods, and specific examples include fluidized dipping method, electrostatic dynamic dipping method, electrostatic powder coating method, and the like. The thickness of the coating layer of the modified olefin polymer can be appropriately selected depending on the conditions of use of the spring, but if sound deadening properties and chipping resistance are taken into consideration, the thickness should be at least 1.
00μ or more, preferably in the range of about 100 to 1500μ.

In the present invention, a thermoplastic synthetic resin or rubber may be coated with a composition comprising the modified olefin compound. These thermoplastic resins include the aforementioned olefin polymers, polyamide resins, polyvinylidene chloride resins, saponified products of ethylene-vinyl acetate copolymers, polyester resins, polyvinyl chloride resins, polybrene resins, Synthetic resins such as ABS resin, polycarbonate resin, polyvinyl alcohol resin, fluorine resin, etc. are used as rubber, ethylene-bu-U-pyrene copolymer rubber,
Synthetic rubbers and natural rubbers such as ethylene-propylene-diene copolymer rubber, polybutadiene rubber, butadiene-styrene copolymer rubber, butadiene-acrylic nitrile rubber, polychloroprene rubber, acrylic rubber, silicone rubber, etc. .

In the present invention, organic or inorganic fillers, antioxidants, lubricants, and various fl or Mtl pigments are used.

UV inhibitor, dispersant, foaming agent, plasticizer, antifoam agent,
Additives such as crosslinking agents, flame retardants, flowability improvers, nucleating agents, etc. may be added to the extent that they do not significantly impair the effects of the present invention.

[Examples] Hereinafter, the present invention will be specifically explained based on Examples and Comparative Examples, but the present invention is not limited to these Examples unless it departs from the gist thereof.

The thermosetting resin, the modified olefin polymer, the coating method, and the test methods for measuring the sound deadening properties, durability, corrosion resistance, adhesive strength, etc. of the samples obtained using these methods are as follows.

(I) Heat-sandable resin (a) Epoxy resin (Product name: Epicoat 0L-53
-8-40, manufactured by Shell Co., Ltd.) (b) Melamine-alkyd resin (trade name: Nidoakalon #1000, Toa Pain Co., Ltd.) (C) Urethane resin (trade name: Niboran 3022, Nippon Polyurethane Co., Ltd.) ) (n) Olefin polymer A) Edylene-ethyl acrylate copolymer (hereinafter simply referred to as EEA) (density 0.931 J/d, melt index 100/10 min, ethyl acrylate containing fi20 shield) m%, manufactured by Nippon Petrochemical Co., Ltd.) B) Ethylene-vinyl acetate copolymer (hereinafter simply abbreviated as EVA) (density 0.93 h
/ cd, melt index 10 (1/10 min,
Contains vinyl acetate (mio weight %, trade name: Nippon Seki Xuron v550, manufactured by Nippon Petrochemical Co., Ltd.) C) Ethylene-butene-1 copolymer (hereinafter referred to as LLDPE)
) (density 0.9240/cd, melt index 14C 1/10 min, product name = 1) Stone Linistsux A
J 5410, manufactured by Nippon Petrochemicals Co., Ltd.) D) Ionomer resin (trade name: Himilan 1652, manufactured by DuPont Mitsui Polychemicals Co., Ltd.) (III) Modified olefin polymer vA product 1 ooai part of each of the above olefin polymers is added with maleic anhydride. Q 0025 parts by weight and dicumyl peroxide 0.02 parts by weight were added and melt-kneaded using an extruder to form modified EEA, modified EVA and modified LLDPE (j
XT-MEEA, MEVA, MLLDPE) were obtained. The maleic anhydride addition M of these was approximately 0.2%.

(IV) Coating method (a) Fluidized dipping method The above modified olefin polymer and/or unmodified olefin polymer are mixed in the prescribed amounts shown in Table 1, pulverized in a pulverizer, and powdered in a 60 mesh (approximately 250μ) bath. As a body.

Using the above powder, pretreated coil springs or steel plates are coated with each of the above thermosetting resins, dried at room temperature, heated to 180°C, placed in a fluidized dipping tank, and coated with the desired film thickness. The coated body was coated as shown in FIG.

(b) Electrostatic powder coating method Using the powder described above, coat a dried coil spring or steel plate with a thermosetting resin to a film thickness of 1300μ with an applied voltage of 60KV, and then apply the coating at 180℃ for 10 minutes. It was then heated to obtain a coated body with a uniform coating film.

(V) Test Method 1: Noise-dampening properties and durability After compressing a coil spring by applying a load to it, the test is repeated at a frequency of 1000 times per minute after the load is removed and the coil spring is returned to its original state, and the sound generated at that time is determined. The number of times the coating film cracks is defined as durability.

2. Resistance (salt water resistance) A coated steel plate was used as a test piece, a scratch was made so as to reach the steel plate, and a 5% NaCl aqueous solution at 35°C was sprayed to determine the time required for rust to develop and peel off. It was measured. LJIS
Z-2371).

3. Using a steel plate as an adhesive strength test piece, after forming a coating film on the steel plate by fluid dipping method or electrostatic powder coating method,
A test piece with a width of 25 fnlR was prepared using the coated body having a uniform coating film by immersion heating for 110 minutes, and a 180° peel test was performed using Tensilon, and the peel strength was defined as the adhesive strength.

As the modified olefin polymer, a mixture of MEEA J3 and MLLDPE with a predetermined ω shown in Table 1 was used, and as the thermosetting resin, an epoxy resin was used. A coil spring or a steel plate was coated by the dipping method (a) to obtain a coating, and the results of evaluation based on the above test method are shown in Table 1.

Examples 4-5 The same procedure as in Example 2 was carried out except that other thermosetting resins shown in Table 1 were used instead of the epoxy resin used in Example 2, and the results are shown in Table 1. .

Example 6 The same procedure as in Example 1 was carried out except that MEVA was used instead of MEEA used in Example 1, and the results are shown in Table 1.

Example 1 was repeated except that a predetermined amount of unmodified LLDPE was mixed with MEEA, and the results are shown in Table 1.

The same procedure as in Example 2 was carried out except that the composition used in Example 2 was used and the film thickness was changed to 1000 μm. The results are shown in Table 1.

Example 10 The same procedure as in Example 2 was conducted except that a composition containing 30 parts of MLLDPE and 70 parts of unmodified EEA was used, and the results are shown in Table 1.

Example 11 The same procedure as in Example 7 was carried out except that the composition used in Example 7 was used and the coating was performed using electrostatic powder coating. The results are shown in Table 1.

Example 1, Example 2, and Example 3 were repeated except that no thermosetting resin was used, and the results are shown in Table 1.

LLIL was carried out in the same manner as in Example 1, except that an ionomer resin was used in place of MEEA used in Example 1, and the results are shown in Table 1.

[Functions and Effects of the Invention FA] As explained above, the synthetic resin-coated spring of the present invention has excellent sound-dampening properties, and has a large adhesive strength between the spring and the Nl1l, so it cannot be easily subjected to repeated stress such as in an automobile suspension system. It has excellent durability even under harsh conditions, and is resistant to damage caused by chipping (chipping resistance), and has a remarkable effect on corrosion resistance, especially salt water resistance, and is suitable for vehicles such as automobiles, ships, aircraft, etc. Used in various fields as industrial parts.

Claims (1)

[Claims] 1. A modified olefin polymer modified with an unsaturated carboxylic acid or a derivative thereof with a thermosetting resin interposed on the surface of the spring, or a combination of the modified olefin polymer and an unmodified olefin polymer. A synthetic resin-coated spring characterized by being coated with a composition. 2. The synthetic resin-coated spring according to claim 1, wherein the surface of the modified olefin polymer or the composition of the modified olefin polymer and unmodified olefin polymer is further coated with a thermoplastic resin or rubber. 3. The synthetic resin covered spring according to claim 1 or 2, wherein the spring is a coil spring. 4. The olefin polymer is any one selected from ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and mixtures thereof. Synthetic resin coated spring according to item 1, 2 or 3. 5. Any one of claims 1 to 4, wherein the thermosetting resin is at least one selected from the group of epoxy resins, melamine resins, alkyd resins, and urethane resins. Synthetic resin coated spring described in . 6. Claim 1, wherein the unsaturated carboxylic acid or its derivative is maleic acid or maleic anhydride.
The synthetic resin coated spring according to any one of Items 1 to 5. 7. Any one of claims 1 to 6, wherein the coating is performed by a powder coating method such as a fluidized dip coating method, an electrostatic dynamic dip coating method, a powder spraying method, or an electrostatic powder coating method. Synthetic resin coated spring described in .