JP2013075636A - Wheel cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel cover film which can be easily removed even if an adhesive remnant is generated while being prevented from being peeled off in transportation of a vehicle or in driving test for a completed vehicle.SOLUTION: The wheel cover film is composed of at least two layers of a substrate layer and an adhesive layer. The adhesive layer includes polyvinyl alcohol or polyvinyl pyrrolidone, or a combination of the mixture.

Description

  The present invention relates to a cover for a wheel of a tire.

In the prior art of the wheel cover for the purpose of protecting the surface of the wheel when the vehicle is transported or exported, there is a vacuum-formed resin wheel cover or wheel cover film.
However, since the vacuum-formed polypropylene wheel cover needs to be manufactured for each wheel shape, it requires a large amount of money to manufacture the mold, and the mold must be stored and managed. Since the storage location is large and it takes a large amount of money to secure it, the economic burden is large. Further, the storage place of the resin wheel cover that is no longer necessary after transportation of the automobile and the economical burden on waste disposal are not preferable.

  On the other hand, as described in Patent Documents 1 and 2, a wheel cover film in which an adhesive such as an acrylic resin is applied to a resin film is also known. In this case, if the adhesive is applied to the entire surface of the resin film, it will be difficult to peel off when the wheel cover is used. Remaining on the surface is a problem. In addition, when the pressure-sensitive adhesive is applied to only a part of the wheel cover film, the wheel cover film may be peeled off due to wind pressure during traveling.

  Moreover, the temperature environment at the time of transportation is various, and the road surface temperature may rise to 60 ° C. from a cold region below 20 ° C. below freezing point. Acrylic adhesives are hard at low temperatures and cannot maintain sufficient adhesiveness against changes in environmental temperature, and the resin itself becomes too soft at high temperatures. It was a problem.

Although it is introduced in patent document 3 to apply | coat an adhesive to this stripping with respect to this peeling, as long as the general-purpose adhesive whose exposed adhesive surface shows adhesiveness for a long time is used, it is low temperature as mentioned above. In addition, there is a concern that the wheel cover film peels off in a high temperature environment.
Most wheels also have shapes with holes and complex irregularities for aesthetic and functional reasons.
When a wheel cover having a general-purpose adhesive layer is affixed to such a wheel surface, the adhesive layer does not adhere to the hole of the wheel or the concave and convex portions of the recesses and is exposed to the space. As a result, the surface of the adhesive layer is exposed on the surface other than the wheel surface. For example, if it is exported unintentionally after attaching insects, seeds, and dust in Japan, There are concerns that problems such as possible destruction will occur.

As described above, the protection of the wheel has advantages that the cover film can deal with any shape of the wheel rather than vacuum forming from the cost of disposal and manufacturing, and that there is no space for storing the waste at the time of disposal.
On the other hand, if the adhesive remains, it takes a process to peel it off, so it takes time during peeling, and the adhesive is exposed in the holes and recesses of the wheel, which may cause unintended destruction of the ecosystem The nature was high. Furthermore, the wheel cover film may be peeled off at low and high temperatures, which is a particular problem in transported automobiles. Therefore, it is not preferable to use a general-purpose pressure-sensitive adhesive such as acrylic for bonding the wheel.

JP 07-309510 A JP 2009-227746 A JP 2009-280128 A

Rather than covering the wheel with a vacuum-formed product, attaching a film-like material to the wheel saves space for storing the used cover as waste.
However, when a film-like material using a general-purpose pressure-sensitive adhesive layer is used, the pressure-sensitive adhesive remains as described above, which takes time during peeling, and faces holes and recesses formed in the wheel. Since the adhesive was exposed, there was a high risk of unintentional destruction of the ecosystem, which had to be eliminated. It is desirable that the wheel cover is attached only to the portion of the wheel surface to be attached, and the adhesive layer is not exposed to unnecessary portions.
Furthermore, the wheel cover film may be peeled off at low and high temperatures, which is a particular problem in transported automobiles. Therefore, it was not preferable to use a general-purpose pressure-sensitive adhesive such as acrylic for bonding the wheel.
In addition, in the present invention, it is also necessary to provide a wheel cover film that does not peel even under a low to high temperature environment.

As a result of intensive studies to achieve the above object, the present inventors have reached the present inventions (1) to (4) below.
1. A wheel cover attached to a wheel of a tire, the wheel cover comprising at least two layers of a base material layer and an adhesive layer, wherein the adhesive layer is a rewet adhesive layer and is water-soluble. Wheel cover.
2. 2. The wheel cover according to 1, wherein a hydrophilic solvent is applied to the surface of the pressure-sensitive adhesive layer or the surface of the adherend and applied to the surface of the pressure-sensitive adhesive layer in an amount of 2 g / g to 20 g / g.
3. The wheel cover according to 1 and 2, wherein the wheel cover has an adhesive strength (JIS Z0237) of 3 to 10 N / 25 mm.
4). The wheel cover according to any one of claims 1 to 3, wherein the adhesive layer is made of polyvinyl alcohol or polyvinyl pyrrolidone or a mixture thereof.

The re-humidifying adhesive layer is made of a water-soluble resin, and the adhesive layer surface is dissolved by touching a hydrophilic solvent to exhibit predetermined adhesiveness. The reason for maintaining the adhesive strength at low and high temperatures is unknown, but the moisture contained in the adhesive layer freezes on the object below the freezing point, increasing the adhesive strength, and at high temperatures the water-soluble resin becomes a solution. Therefore, it can be inferred that there is little change in viscosity and a stable adhesive strength is exhibited.
Although such water-soluble resins are affected by the humidity of the environment in which they are used, the base material layer prevents moisture from entering the environment and suppresses diffusion of the solvent contained in the water-soluble resin into the atmosphere. To do. Therefore, the wheel cover can maintain the adhesive strength of the adhesive layer in a wide temperature environment.
Furthermore, when the wheel cover is peeled after use, it can be peeled without leaving the pressure-sensitive adhesive on the wheel surface, so that a step of peeling the pressure-sensitive adhesive remaining on the surface by means such as washing is not required.
In addition, when a wheel cover is affixed to a wheel surface having holes or irregularities, the water content decreases as the adhesive layer surface of the wheel cover facing the holes or recesses dries over time. Disappears. As a result, even if insects or dust come into contact with the dried adhesive layer surface, they do not adhere to the surface, so it is possible to move insects and seeds to the destination along with transportation of automobiles and wheels. Can be prevented. For this reason, there is no problem in terms of quarantine and ecosystem.

Hereinafter, the present invention will be described in detail based on preferred embodiments.
The wheel cover of the present invention is attached to the wheel surface of a tire to prevent water, sand, and the like from adhering to the wheel surface, brake disc, and the like from the outside, thereby preventing the occurrence of rust. Moreover, it protects the wheel and prevents the wheel from being scratched by a stone or the like.
Such a wheel cover has an annular shape in which a base material layer and an adhesive layer are laminated, and a hole for accommodating a wheel nut is opened in the center, which matches the size of the wheel.

  The adhesive layer consists of a rewetable adhesive that exhibits adhesiveness only after it is wetted with a hydrophilic solvent immediately before use, and allows a base material layer having a function of protecting the wheel to be attached to an object. It is a premise. By adopting such an adhesive layer, it is possible to adhere to the shape of various wheels in a wide temperature range, and no adhesive remains on the wheel surface at the time of peeling. Is.

The base material layer has a function of preventing water and sand from adhering to the wheel surface when attached to the wheel, and also has a function of suppressing the volatilization of the hydrophilic solvent applied to the adhesive layer. . In addition, the automobile with the wheel cover attached is subjected to high-pressure water washing using water before shipment from the manufacturing factory, but the base material layer also plays a role in preventing the moisture from being wetted on the adhesive layer. .
The base material layer is not particularly limited as long as it has the above-described function. Therefore, it is necessary that the base material layer has water resistance, low moisture permeability, water insolubility, and is not damaged by sand or stone. For this reason, materials having moisture permeability such as paper and porous sheets are not suitable for the base material layer.
Base materials used in the present invention include olefin resins such as polyethylene resins and polypropylene resins, polyester resins such as polyethylene terephthalate resins and polynaphthalene terephthalate resins, polyvinyl chloride resins, polycarbonate resins, ethylene-propylene copolymers, Various resins such as ethylene-vinyl acetate copolymers, ethylene copolymers such as ionomers, thermoplastic polyolefin resins, thermoplastic polyester elastomers, and polylactic acid resins can be used. Among the above, polyethylene resin is preferable from the viewpoint of low moisture permeability and high flexibility.

For the purpose of improving processability and handling properties, plasticizers, excipients, UV absorbers, antioxidants, antistatic agents, rust inhibitors, antiblocking agents, etc. are added to the base material layer as necessary. Also good.
Although the thickness of a base material layer is not specifically limited, The range of 10-2000 micrometers is preferable, More preferably, it is 20-200 micrometers. If it is less than 10 μm, it is easy to break, and there is a possibility that the base material layer will be hit with stones, etc., and if it exceeds 200 μm, the base material layer will become hard and follow the curved surface of the wheel surface to cover and adhere closely. It can be difficult.

The pressure-sensitive adhesive layer is made of a rehumidifying pressure-sensitive adhesive that is humidified and exhibits pressure-sensitive adhesive properties, and is made of a pressure-sensitive adhesive containing a water-soluble resin. Adhesive that disappears is used. Examples of the adhesive include cellulose resins such as hypromellose and methylcellulose, polyvinyl alcohol resins, polyvinylpyrrolidone resins, polyvinylpyrrolidone-vinyl acetate copolymers, and polysaccharides such as gum arabic, guar gum, locust bean gum Resin can be used.
Among these, in order to maintain the adhesiveness after wetting, an adhesive layer containing a polyvinyl pyrrolidone resin in a polyvinyl alcohol resin or an adhesive layer containing a resin obtained by polymerizing polyvinyl pyrrolidone in polyvinyl alcohol is preferable. The reason for this is that the film does not exhibit tackiness but does not exhibit tackiness for the first time when it is wetted with a hydrophilic solvent, and maintains good tackiness even when the pressure-sensitive adhesive layer reaches the equilibrium moisture content.

Furthermore, the above-mentioned polyvinyl alcohol has a degree of polymerization of 100 to 4000, or polyvinyl pyrrolidone in mixing polyvinyl pyrrolidone or polymerizing polyvinyl pyrrolidone is preferably 10% by weight or more.
Especially, it is preferable that the saponification degree of polyvinyl alcohol is 70-100 mol%, and 70-99 mol% is more preferable. If the saponification degree of polyvinyl alcohol is less than 70 mol%, the adhesiveness is lowered. The saponification degree is more preferably 74 mol% or more, and particularly preferably 88 mol% or more, but when it exceeds 99 mol%, it becomes difficult to re-wet.
In addition, polyvinyl alcohol resin and polyvinyl pyrrolidone resin used for the adhesive layer contain a small amount of moisture and acetate, but the content is not so much as to induce rust.

  The method for producing the pressure-sensitive adhesive layer may be obtained by casting the aqueous solution of the rewet pressure-sensitive adhesive resin on an endless belt or a dryer and drying it by heating. What is necessary is just to produce the wheel cover which melt-extruded with the base material layer, or formed the multilayer by carrying out the heat lamination or wet lamination of the water-soluble adhesive film to a base material layer. These production methods can be appropriately selected according to the characteristics of such a resin.

In the adhesive layer, plasticizers and antiblocking agents, excipients, antistatic agents, surfactant pigment dispersants, thickeners, fluidity improvers, pH adjusters, antifoaming agents, antifoaming agents, Various additives such as a mold release agent, a foaming agent, a penetrating agent, a hardening agent, an antiseptic, a baitproofing agent, a water resistant agent, a dye, an ultraviolet absorber, and an antioxidant may be added as necessary. In addition, there is no problem even if two or more kinds of water-soluble resins are mixed and used.
In the pressure-sensitive adhesive layer used in the present invention, pigments and the like can be added as long as the object of the present invention is not hindered. For example, carbonates, oxides, hydroxides of aluminum, zinc, calcium, magnesium, barium, titanium, etc. Used, inorganic pigments including clays such as natural silica, zeolite, kaolin, calcined kaolin, starch, styrene resin, polyolefin resin, melamine resin, acrylic resin, paraffin, natural wax, synthetic wax, etc. Is possible.

The thickness of the adhesive layer is preferably in the range of 10 to 2000 μm, more preferably 20 to 200 μm, and still more preferably 30 to 100 μm. If the thickness of the pressure-sensitive adhesive layer is less than 10 μm, it cannot have a sufficient pressure-sensitive adhesive force, and if it has a thickness exceeding 2000 μm, the pressure-sensitive adhesive force may be too strong.
The adhesive strength of the adhesive layer to the aluminum wheel is in the range of 2 to 10 N / 25 mm, which further protects the wheel surface more reliably, prevents inadvertent peeling during protection, and ensures that the peel is peeled off. This is preferable for easily performing the peeling operation without remaining.

The wheel cover of this invention needs to peel the film for wheel covers adhering to a wheel, without adhesive residue, after conveyance of a motor vehicle. For this reason, the adhesive force between the adhesive layer and the wheel needs to be lower than the adhesive force between the base material layer and the adhesive layer and the cohesive force of the adhesive layer, and the adhesive layer must be water-soluble. It is.
If the adhesive force between the adhesive layer and the wheel is higher than the adhesive force between the base material layer and the adhesive layer, when the wheel cover is peeled from the wheel, it will be peeled exclusively between the base material layer and the adhesive layer. Thus, most of the pressure-sensitive adhesive layer remains on the wheel surface after peeling, and then a step of dissolving and removing the remaining pressure-sensitive adhesive layer by applying a hydrophilic solvent is required.
Thus, in the present invention, when the wheel cover is peeled off, it is necessary that no adhesive layer remains on the wheel surface, that is, no adhesive residue is generated.

  However, if the adhesive layer is peeled off the wheel and the adhesive layer adheres to the wheel to such an extent that there is no adhesive residue on the wheel, the wheel cover is being used if the adhesive layer's adhesive strength to the wheel is too low. In addition, the wheel cover is easy to peel off from the wheel, and there is a possibility that troubles such as inability to sufficiently protect the wheel may occur.

  In addition, when the adhesive force between the adhesive layer and the wheel is higher than the cohesive force of the adhesive layer, the cohesive failure occurs inside the adhesive layer by peeling off the wheel cover, and some of the adhesive layers are on the wheel surface. As a result, a part of the adhesive layer adheres to the base material layer. Even in this case, it becomes necessary to dissolve and remove the remaining adhesive layer by applying a hydrophilic solvent thereafter.

  In particular, when the base material layer is made of a material having low adhesion to the adhesive layer such as polyolefin resin or fluororesin, a primer layer may be provided between the base material layer and the adhesive layer, or the adhesive layer of the base material layer Surface treatment, such as corona discharge treatment, can be performed on the surface on the side where the film is provided.

  In addition, when storing before using the wheel cover of the present invention, a release film is previously applied to the surface of the adhesive layer so that the surface of the adhesive layer does not deteriorate due to dirt or dust adhering to the surface of the adhesive layer. You may protect by sticking. Moreover, in the dry state, when the adhesive layer surface does not have adhesive force, it is not always necessary to attach such a release film.

A wheel cover comprising at least two layers of a base material layer and an adhesive layer can be attached with the adhesive surface in contact with the wheel side to prevent water and dust from entering the wheel. The adhering method may be applied to the surface of the pressure-sensitive adhesive layer or the surface of the wheel by spraying a hydrophilic solvent by spraying or brushing, and it is more preferable to apply the hydrophilic solvent to the surface of the wheel without exposing an excessive pressure-sensitive adhesive surface. .
As the hydrophilic solvent, water, alcohols such as ethanol and glycol can be used. However, it is desirable to employ water or ethanol in consideration of easy availability.
The amount of the hydrophilic solvent used is desirably in the range of 2 to 20 g, that is, 2 to 20 g / g with respect to the unit weight of the adhesive layer. Preferably it is 5-15 g / g. If it is less than 2 g / g or exceeds 20 g / g, sufficient adhesive strength cannot be exhibited. For example, when the polyvinyl alcohol has a high degree of polymerization or a high degree of saponification, the adhesive force can be exhibited even if the amount of the hydrophilic solvent is large.

The target wheel for which the wheel cover of the present invention is used may be a wheel made of a known wheel material such as aluminum or steel. Furthermore, the wheel may be a wheel used in a known vehicle using a wheel such as for automobiles and motorcycles.
The wheel cover of the present invention is used mainly for wheels that need to be protected, such as wheels shipped from factories, warehouses, shops, etc., or wheels that are assembled to an axle and integrated with a vehicle.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. An Example is shown about the composition which contains polyvinyl alcohol and polyvinylpyrrolidone in the adhesion layer.

(Sample evaluation)
○ Measurement of moisture content of adhesive layer Using a precision scale, the difference in film weight between before and after spraying when applying a hydrophilic solvent with a spray hole 20cm away from the plane of the wheel cover of 25mm x 20cm square in the vertical direction The amount of water (g) given to the adhesive layer was measured. The value was divided by the weight of the adhesive layer to determine the amount of water (g / g) relative to the adhesive layer.

○ Adhesive evaluation Under an atmosphere of 23 ° C.-50% RH, the adhesive strength against an aluminum wheel by 180 ° peeling method after 24 hours of pasting measured in accordance with JIS Z0237 (hereinafter referred to as “adhesive strength (unit: N / 25 mm) ”). However, in order to evaluate the influence of the temperature of the adhesive strength, the measurement method is similarly changed and only the measurement environment temperature is changed in the range of -30 ° C to 80 ° C.
Based on the value of adhesive strength, it is classified into the following three stages.
Wheel cover showing 2N / 25mm or more and 10N / 25mm or less
Wheel cover less than 2N / 25mm or greater than 10N / 25mm ... ×

○ Judgment of remaining adhesive marks Wheel surface when the wheel cover is peeled off after 2 hours after the pressure-sensitive adhesive layer obtained by wetting a 25 mm x 20 cm square wheel cover with a hydrophilic solvent is pressed onto the aluminum wheel surface. Was visually observed for the presence or absence of the adhesive layer.
It is classified into the following two stages according to the presence or absence of glue residue.
Wheel cover with no glue marks left
Wheel cover with traces of glue

○ Comprehensive judgment criteria for wheel cover When the adhesive strength is “○” and the adhesive residue is “○”… ○
When the adhesive strength is “○” and the adhesive residue is “×” ... ×
When the adhesive strength is “×” and the adhesive residue is “O” ... ×
When the adhesive strength is “×” and the adhesive residue is “×” ... ×

  Thermal lamination of an adhesive layer having a thickness of 40 μm made of partially saponified polyvinyl alcohol (manufactured by Nippon Acetate / Poval) with a polymerization degree of 1000 and a saponification degree of 88.0 mol% to a base layer made of low-density polyethylene having a thickness of 60 μm Thus, a multilayer film was obtained. Distilled water was applied to the adhesive layer as a hydrophilic solvent on the adhesive layer side to obtain a wheel cover sample 1.

  A pressure-sensitive adhesive layer having a thickness of 30 μm comprising a low saponified polyvinyl alcohol having a polymerization degree of 500 and a saponification degree of 74.5 mol% (made by Kuraray Co., Ltd.) containing 20 wt% polyvinylpyrrolidone K-30 and 10 wt% glycerin as a plasticizer. A multilayer film was obtained by wet lamination with a base material layer made of polypropylene. Methanol was applied to the adhesive layer as a hydrophilic solvent on the adhesive layer side to obtain a wheel cover sample 2.

[Comparative Example 1]
An adhesive containing an organic solvent made of an acrylic resin and a styrene resin is used as the adhesive layer, and the adhesive layer is applied to a low-density polyethylene substrate layer having a thickness of 60 μm so as to have a thickness of 10 μm. Sample 3 was obtained.

(result)
In Example 1, the moisture content of Sample 1 was fixed at 8 g / g, and the adhesive strength to aluminum was measured when the temperature of the adhesive layer was −30 to 80 ° C., and there was no adhesive trace remaining on the aluminum wheel. It was confirmed.
As shown in the following table, when the aluminum wheel is left outdoors, the adhesive strength is in the range of 2 to 10 N / 25 mm in the range of -20 to 80 ° C., which is the temperature range in which the aluminum wheel can occur, and Since there was no adhesive mark remaining on the aluminum wheel, the overall judgment was excellent.
In other words, in this temperature range, the wheel cover can be adhered to the aluminum wheel with a sufficiently strong adhesive force, and there can be exhibited an effect that it can be peeled cleanly with no adhesive residue remaining at the time of peeling. It was.
On the other hand, when the temperature is −30 ° C., the adhesive force of the adhesive layer is reduced and the adhesive force is less than 2 N / 25 mm. Therefore, at this temperature, the wheel cover is not sufficiently adhered to the aluminum wheel by the adhesive force. Therefore, since the wheel cover may actually be peeled off from the aluminum wheel, the comprehensive judgment was not a good result.

Moreover, when the moisture content given to the pressure-sensitive adhesive layer of the wheel cover is 1 to 24 g / g and the temperature of the pressure-sensitive adhesive layer is fixed at 24 ° C., when the moisture content is in the range of 3 to 19 g / g, It can be seen that it is excellent in comprehensive judgment because it is adhered to the aluminum wheel by an adhesive force in the range of 2 to 10 N / 25 mm and can be peeled without any adhesive residue.
When the amount of water was small and the amount was 1 g / g, the pressure-sensitive adhesive layer of the wheel cover could not have sufficient adhesive force, and was only less than 2 N / 25 mm. Conversely, even when the moisture content of the adhesive layer was as high as 24 g / g, the adhesive force of the adhesive layer of the wheel cover was not sufficiently strong, and was only less than 2 N / 25 mm as in the low case. The overall judgment on these results was not good.
As is apparent from this result, it can be understood that the adhesive strength of the adhesive layer decreases after the moisture content is low, that is, after the moisture has evaporated from the adhesive layer. When protecting the wheel surface, if the pressure-sensitive adhesive layer facing the hole in the wheel or the concave portion of the surface unevenness is dried and the water content decreases, the adhesive strength of the pressure-sensitive adhesive layer does not attach insects, dust, etc. To drop.

  The example which changed the composition of the adhesion layer with respect to Example 1 is Example 2, and in Example 2, the moisture content of the adhesion layer was 5 g / g, and the temperature was −20 ° C., 23 ° C. and 60 ° C. In any case, the adhesive strength of the adhesive layer is in the range of 2 to 10 N / 25 mm in any case, and there is no adhesive mark residue when the wheel cover is peeled off from the aluminum wheel, so the overall judgment is also excellent. there were.

In contrast to Examples 1 and 2 as described above, as Comparative Example 1, the moisture content of the adhesive layer was set to 0 g / g. That is, since the organic solvent-containing adhesive layer is employed, an adhesive layer that does not need to supply moisture to the adhesive layer is employed. Then, the adhesive strength was measured with the temperature of the adhesive layer in the range of −30 to 80 ° C., and the adhesive residue was confirmed.
As a result, when the temperature of the adhesive layer is 15 ° C. and 23 ° C., the adhesive strength is in the range of 2 to 10 N / 25 mm, but at other temperatures, the adhesive strength is not in the range of 2 to 10 N / 25 mm. Adhesive strength not suitable for the wheel cover of the present invention was shown.
Furthermore, under all temperature conditions, adhesive residue remained when the wheel cover was peeled from the aluminum wheel. As a result, the comprehensive judgment does not give a good judgment result in all temperature ranges, and it can be understood that the pressure-sensitive adhesive used in Comparative Example 1 is unsuitable for the pressure-sensitive adhesive used in the present invention. .

Claims (4)

  A wheel cover attached to a wheel of a tire, the wheel cover comprising at least two layers of a base material layer and an adhesive layer, wherein the adhesive layer is a rewet adhesive layer and is water-soluble. Wheel cover.   The wheel according to claim 1, wherein a hydrophilic solvent is applied to the surface of the adhesive layer or the adherend surface by applying 2 g / g to 20 g / g based on the weight of the adhesive layer, and the adhesion is exhibited. cover.   The wheel cover according to claim 1 or 2, wherein the wheel cover has an adhesive strength (JIS Z0237) of 3 to 10 N / 25 mm.   The wheel cover according to any one of claims 1 to 3, wherein the adhesive layer is made of polyvinyl alcohol or polyvinyl pyrrolidone or a mixture thereof.