JP5383986B2 - UV-absorbing polymer material - Google Patents

Description

  The present invention relates to an ultraviolet absorber, and more specifically, is made of an ionomer of a specific metal ion, has an excellent ultraviolet absorbing ability without using an ultraviolet absorber, and has a visible light region or a near infrared light region. The present invention relates to a UV-absorbing polymer material that is excellent in light transmittance and excellent in processability to molded products such as films and sheets.

In the past, many UV-absorbing materials that absorb and cut ultraviolet rays contained in sunlight, etc. in order to protect human skin, etc. and prevent material deterioration, and UV protection articles that are molded and processed are commercially available. It is provided.
In particular, the retraction phenomenon of the ozone layer surrounding the earth has recently been taken up as a major problem, and the provision of a new and effective ultraviolet absorber has been attracting attention in order to prevent damage caused by an increase in the amount of ultraviolet rays due to the destruction of the ozone layer.

As an ultraviolet absorbing material, for example, for film and sheet materials, conventionally, a resin composition in which various organic and inorganic ultraviolet absorbers are blended with a thermoplastic resin such as soft vinyl chloride, polyethylene, ethylene / vinyl acetate copolymer, etc. Have been used extensively, and many proposals for improvement have been submitted.
For example, Patent Document 1 discloses an invention of an agricultural film composition in which a triazine-based ultraviolet absorber having a specific chemical structural formula is blended with a polyethylene-based thermoplastic resin.

However, in order to obtain a homogeneous resin composition, it is necessary to select an ultraviolet absorber having high compatibility and affinity with the resin, and a homogeneous composition is required depending on the combination of the resin species and the ultraviolet absorber species. It may be difficult to obtain.
In addition, when blending an ultraviolet absorber into a resin, depending on the type or amount of the absorber, there are problems such as decomposition, volatilization, sublimation, contamination due to bleedout, etc. by heating at a temperature required for resin molding. Arise.

  For this reason, it is possible to efficiently absorb ultraviolet rays only with a resin without blending an ultraviolet absorber, and has high transparency to visible rays and near-infrared rays, but still processability of products such as films and sheets. There has been a strong demand for a polymer (resin) material excellent in the above-mentioned.

  An ultraviolet absorbing material made of a resin not containing an ultraviolet absorber has already been proposed, and Patent Document 2 discloses a hydrazine compound such as hydrazine added to a polymer having a nitrile group such as acrylonitrile or acrylonitrile / methyl acrylate copolymer. There has been proposed an ultraviolet-absorbing material containing an introduced cross-linkable polymer as an active ingredient.

However, since the ultraviolet absorbing material of the present invention is composed of a crosslinkable polymer, a reaction step for crosslinking a nitrile group-containing polymer with a hydrazine derivative is required, and extra labor, time, and cost are required.
In addition, once the cross-linking is performed, there is a problem that it is difficult to perform a processing that greatly deforms the shape of the article. In this respect, use may be limited depending on the application.
Accordingly, there has been a demand for an ultraviolet absorber made of a thermoplastic resin that can be freely subjected to free deformation.

JP 2006-117833 A JP 2004-256573 A

  The present inventors use an ethylene / methacrylic acid copolymer as a base resin, and rare earth metal elements such as cerium (Ce), niobium (Nb), tantalum (Ta), and other metal elements generally used as commercial products. In the research to investigate the physical properties of ionomers using various metal elements, Ce and Ta ion ionomers happened to be in the visible light region and near infrared region. It has been found that it exhibits high light transmission in the light region, while it exhibits extremely high light absorption in the ultraviolet light region having a wavelength of 350 nm or less.

Therefore, the object of the present invention is to show an excellent ultraviolet absorption ability without blending an ultraviolet absorber, and to be excellent in light transmittance in the visible light region and near infrared light region, and it is still a film and sheet. Another object of the present invention is to provide a polymer material having an ultraviolet absorbing ability excellent in processability to a molded article such as the above, and an ultraviolet absorbing material (cut) material made of the polymer material.
Furthermore, another object of the present invention is to provide a molded product obtained by molding the above-described ultraviolet absorbing material, in particular, a film or sheet comprising the material.

According to the present invention, polymeric materials having excellent ultraviolet absorption capacity consists tantalum (Ta) ionomer of an ethylene-unsaturated carboxylic acid copolymer are provided. In order to obtain excellent ultraviolet absorption performance in the present invention, the ethylene / unsaturated carboxylic acid copolymer as the base polymer preferably has an unsaturated carboxylic acid unit content of 2 to 30% by weight, neutralization degree of the ionomer of tantalum (ion) is preferably 10 mol% or more.
The ethylene / unsaturated carboxylic acid copolymer is preferably composed of an ethylene / (meth) acrylic acid copolymer.
In addition, the polymer material excellent in ultraviolet absorbing ability of the present invention preferably has a mode in which zinc oxide (ZnO) fine powder is further blended with the ionomer.
In addition, the present invention provides a molded article formed by molding the polymer material excellent in ultraviolet absorbing ability , particularly a film or sheet made of the polymer material excellent in ultraviolet absorbing ability .

The ultraviolet absorbing material of the present invention is composed of a specific metal ion ionomer of an ethylene / unsaturated carboxylic acid copolymer and has an excellent ultraviolet absorbing ability without blending an ultraviolet absorber, and has a light in the visible light region. Excellent permeability, but also excellent in molding and workability.
Therefore, molded products that require UV cut and UV durability, such as molded products such as hoses, tubes, building materials, automotive exterior parts, cosmetic containers, pharmaceutical containers, agricultural films and sheets, food packaging films, etc. It is suitably used as an ultraviolet absorbing film or sheet.

Hereinafter, the present invention will be described in detail and specifically with reference to a partial diagram.
Polymeric material and an ultraviolet absorber having an ultraviolet absorbing ability of the present invention consists of tantalum (Ta) ionomer of an ethylene-unsaturated carboxylic acid copolymer.

In the present invention, the unsaturated carboxylic acid component of the ethylene / unsaturated carboxylic acid copolymer which is the ionomer base resin includes acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, maleic acid, monomethyl maleate, and maleic anhydride. Etc.
Of these, acrylic acid or methacrylic acid is preferred.
In the present invention, the ethylene / unsaturated carboxylic acid copolymer is not only a binary copolymer of ethylene and an unsaturated carboxylic acid, but also an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer. A multi-component copolymer containing ethylene and unsaturated carboxylic acid such as a polymer is also included in the category.
The unsaturated carboxylic acid ester component in the ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer is an alkyl ester having 1 to 20 carbon atoms of each carboxylic acid used in the unsaturated carboxylic acid component. Specific examples of the alkyl group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 2-ethylhexyl, isooctyl and the like.
Of these, alkyl esters of acrylic acid or methacrylic acid, particularly methyl, ethyl and isobutyl esters of acrylic acid or methacrylic acid are preferred.

The ethylene / unsaturated carboxylic acid copolymer used in the present invention has a melt flow rate (MFR) of 1 to 1000 g / 10 min at 190 ° C. and 2160 g load (according to JIS K7210), particularly 10 to 500 g / 10. It is preferable from the viewpoint of imparting strength to a molded product that can be obtained.
In the present invention, the copolymer may be a combination of a plurality of unsaturated carboxylic acid species or different types of polymerization compositions, and a copolymer composed of a plurality of copolymers having different unsaturated carboxylic acid species is molded. There is also an advantage that fine adjustment of the melt viscoelasticity during processing is possible.

  In the ethylene / unsaturated carboxylic acid copolymer, the content of unsaturated carboxylic acid units such as (meth) acrylic acid units is particularly excellent in UV absorption performance from the viewpoint of mechanical and optical properties of the resulting ionomer. From the viewpoint of obtaining, it is preferably in the range of 2 to 30% by weight, preferably 9 to 25% by weight, and particularly preferably in the range of 12 to 20% by weight.

  According to a known method for producing this type of copolymer resin, the copolymer is a mixture of ethylene and an unsaturated carboxylic acid such as (meth) acrylic acid ester at a high temperature, a high pressure, for example, a pressure of 100 to 200 MPa, It can be obtained by direct copolymerization by high-pressure free radical polymerization under reaction conditions such as a temperature of 150 to 300 ° C.

Ionomers of the present invention has been neutralized partially or all carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer with tantalum (Ta) ions.
Tantalum (Ta) is one vanadium group elements belonging to the periodic table group 5, present as an oxidation number of 3, 4, 5.

The ionomer of the present invention, the neutralization degree of tantalum (ions) of the carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer in order to obtain an excellent ultraviolet absorbing performance, preferably at least 10%, in particular 30 to 60 % Is preferred.
The 190 ° C. of tantalum (Ta) ions ionomer of ethylene-unsaturated carboxylic acid copolymer, in melt flow rate 2160g load (according to JIS K7210) (MFR) is 0.01 to 100 g / 10 min, in particular It is preferable from the viewpoint of imparting strength to a molded product obtained to be 0.1 to 50 g / 10 min.

Next, a process for the preparation of an ionomer of the present invention, will be described as an example when preparing T a ionomer of Karaso ethylene-methacrylic acid copolymer base resin.
An ethylene / methacrylic acid copolymer having a desired methacrylic acid unit content is selected and prepared as a base resin, and a predetermined amount of Ta salt powder taking into account the carboxylic acid unit content of the resin, the desired degree of neutralization, etc. Alternatively, the solution is added and, for example, ionomer is kneaded at a temperature of about 100 to 250 ° C. at a stirring speed of about 20 to 150 rpm for about 5 to 50 minutes using a kneading apparatus such as a plastmill single or twin screw extruder. Get the material.
This is directly or once made into a pellet or the like, and then molded into a desired shape such as a film or sheet.

The copolymer resin further includes, for example, an antioxidant such as hydroquinone monobenzyl ether and triphenyl phosphite, a heat stabilizer such as lead stearate and barium laurate, a filler such as fine titanium oxide and zinc oxide, and the like. Various additives can be blended.
In particular, ultrafine inorganic powders called so-called nanofillers as fillers, for example, those containing ultrafine zinc oxide (ZnO) powder having a particle size of about 1 to 100 nm have a more ultraviolet absorption effect in the near ultraviolet region. It is favorable because it does not substantially reduce the light transmittance in the visible region or near infrared region, and there is no contamination due to bleedout of low molecular weight components.

  The polymer material excellent in ultraviolet absorbing ability of the present invention thus obtained can be molded and processed in the same manner as general ionomer materials, and is mainly used as an ultraviolet absorbing material (ultraviolet ray cutting material), particularly as an ultraviolet ray absorbing material. And molded products that require UV durability, such as hoses, tubes, building materials, automotive exterior parts, cosmetic containers, pharmaceutical containers, etc. It is preferably used as an ultraviolet absorbing film or sheet such as a food packaging film.

For reference, a spectrophotometric diagram of a film obtained from Ce ionomer is shown in FIG.
The figure shows (1) Ce ionomer ( reference product : base resin; ethylene / methacrylic acid copolymer, methacrylic acid content = 15 wt%, MFR = 60 g / 10 min, density 940 kg / m ³⁾ ; (Neutralization degree of carboxyl group with Ce (ion) 30%), (2) Commercially available Zn ionomer (Comparative Example product: High Milan H1706 manufactured by Mitsui DuPont), and (3) Zinc oxide super A transmittance (T:%) for light in a wavelength region of 200 nm to 2200 nm of a press sheet (thickness is about 500 μm) composed of a composition (comparative product) containing 1000 ppm of fine particles (average particle size: 20 nm). FIG.

From FIG. 1, the Ce ionomer (1) which is a reference product shows light transmittance almost equal to that of the commercially available Zn ionomer (2) in the visible light wavelength region and the infrared wavelength region, and is more than the fine ZnO compounding composition (3). Clearly excellent in light transmission.
On the other hand, in the ultraviolet wavelength region, the transmissivity is much lower than that of the composition (3), which shows a remarkably low transmittance (high absorptivity) with respect to the commercially available Zn ionomer (2) and is said to be excellent in ultraviolet absorptivity. I understand that.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited by the description of these examples. In the following Examples and Comparative Examples, the criteria for evaluating the ultraviolet absorption characteristics, visible light transmittance, and bleed out properties are as follows.
UV absorption characteristics:
A: The transmittance of light wavelengths of 350 nm, 330 nm, and 300 nm is smaller than the transmittance of visible light of 500 nm, and in particular, the transmittance of 300 nm is 0%.
○: The transmittance at a light wavelength of 300 nm is less than 10%.
(Triangle | delta): The transmittance | permeability of the light wavelength of 300 nm is less than 20%.
X: The transmittance at a light wavelength of 300 nm is 20% or more.
Visible light transmittance:
A: The transmittance at a light wavelength of 500 nm in the visible light region is 80% or more.
○: The transmittance at a light wavelength of 500 nm in the visible light region is 70% or more.
(Triangle | delta): The transmittance | permeability of the light wavelength of 500 nm of visible light region is 50% or more.
X: The transmittance at a light wavelength of 500 nm in the visible light region is less than 50%.
Breed-out characteristics:
○: No change in surface condition is observed even when a specimen of 500μm thickness is exposed to an atmosphere of 40 ° C x 90% RH for 3 months.
×: When a specimen having a thickness of 500 μm is exposed to an atmosphere of 40 ° C. × 90% RH for 3 months, the surface of the specimen is contaminated with low molecular weight components.

"Example 1" (reference example)
Ethylene / methacrylic acid copolymer (methacrylic acid content = 15 wt%, MFR = 60 g / 10 min, density 940 kg / m ³ was used as the base resin, and cerium acetate (Ce (CH ₃ COO) ₃ ) fine powder was used in this resin In a lab plast mill at 190 ° C. and a stirring speed of 40 rpm for about 40 minutes, so that the neutralization degree is 30% (that is, 30% of the carboxyl groups of the base resin are neutralized with Ce (ions)). ) A Ce ionomer material was obtained.
A press sheet having a thickness of 500 μm was produced using this material by a heat compression molding machine.
The transmittance (T%) of the sheet sample cut from this was measured in an optical wavelength scanning range of 200 to 2200 nm with an ultraviolet-visible infrared spectrophotometer (UVpc manufactured by Shimadzu Corporation).
The obtained spectrophotometric diagram is shown in FIG. 1 (symbol (1)).
As is clear from FIG. 1 (1), the sheet of Example 1 exhibits extremely excellent ultraviolet light absorption ability, and the light transmittance is 31.6% at a wavelength of 350 nm, 2.0% at 330 nm, and 0% at 300 nm. is there.
On the other hand, at a wavelength of 500 nm, which is a visible light region, the transmittance is 83.3%, and the transmittance is close to that of a commercially available Zn ionomer sheet having excellent transparency.

"Example 2"
Using the same resin as the base resin used in Example 1, fine powder of tantalum (V) ethoxide (Ta (OC ₂ H ₅ ) ₅ ) was added, and about 40 at 190 ° C. and a stirring speed of 40 rpm in a lab plast mill. A Ta ionomer material having a degree of neutralization of 30% (that is, 30% of the carboxyl groups of the base resin was neutralized with Ta (ions)) was obtained.
This was formed into a sheet in the same manner as in Example 1 and spectrophotometrically measured in the same manner as in Example 1.
As a result, the light transmittance was 64.6 % at a wavelength of 350 nm, 27.9% at 330 nm, and 0% at 300 nm.
Further, the transmittance was 84.8% at a wavelength of 500 nm. Table 1 shows the results of Example 2.

"Comparative Example 1"
To prepare a press sheet having a thickness of 500μm from commercial Zn ionomer (Mitsui DuPont milan H1706) material.
The transmittance (T%) of the sheet sample cut from this was measured in an optical wavelength scanning range of 200 to 2200 nm with an ultraviolet-visible infrared spectrophotometer (UVpc manufactured by Shimadzu Corporation).
The obtained spectrophotometric diagram is shown in FIG. 1 (symbol (2)).
The light transmittance is 84.8% at a wavelength of 350 nm, 83.1% at 330 nm, and 66.8% at 300 nm.
Moreover, the transmittance | permeability 88.6% was shown in wavelength 500nm which is a visible light region.
Table 1 shows the results of Comparative Example 1.

"Comparative Example 2"
70 g of the same Zn ionomer as Comparative Example 1 was blended with 0.07 g of ultrafine zinc oxide (ZnO: nanofiller: average particle size of about 20 nm) and kneaded in a Laboplast mill at 130 ° C. and a stirring speed of 40 rpm for about 20 minutes. Thus, a Zn ionomer composition containing zinc oxide fine particles was obtained.
This was formed into a sheet in the same manner as in Example 1 and spectrophotometrically measured in the same manner as in Example 1.
The obtained spectrophotometric diagram is shown in FIG. 1 (symbol (3)).
The light transmittance is 36.9% at a wavelength of 350 nm, 31.8% at 330 nm, and 16.9% at 300 nm.
Further, the transmittance was 78.1% at a wavelength of 500 nm which is a visible light region.

Table 1 below shows the results of Examples 1 and 2 and Comparative Examples 1 and 2.

"Comparative Examples 3-11"
From the same base resin used in Example 1, Yb, Dy, Ho, Nd, Gd, Er, Cs, Sm, and Nb metal ion ionomers (all neutralization degrees are about 30%) were prepared. The sheet was molded in the same manner as in Example 1, and the spectrophotometric measurement was performed in the same manner as in Example 1.
The measurement results are summarized in Table 2.

From the results shown in Table 2, it can be seen that the metal element ions other than Ce (reference product) and Ta (present invention) cannot realize the excellent ultraviolet absorption function of the present invention product even if it is a metal element of the same family. .

Spectral photometric diagram of the present invention product and comparative product film and sheet

Explanation of symbols

1 real施例1 (Ce ionomer; reference product)
2 Comparative Example 1 (Zn ionomer)
3 Comparative Example 2 (ZnO fine particle blend composition)

Claims (8)

Other ethylenically-unsaturated carboxylic acid copolymer tantalum (Ta) polymeric materials having excellent ultraviolet absorptivity ionomers.   The polymer material according to claim 1, wherein the content of unsaturated carboxylic acid units in the ethylene / unsaturated carboxylic acid copolymer is 2 to 30% by weight. Polymeric material according to claim 1 or 2, wherein data Ntaruion degree of neutralization of the ionomer is 10% or more. The polymer material according to any one of claims 1 to 3, wherein the ethylene / unsaturated carboxylic acid copolymer comprises an ethylene / (meth) acrylic acid copolymer. The polymer material according to any one of claims 1 to 4, wherein zinc ion (ZnO) fine powder is further blended with the ionomer. A molded article formed by molding the polymer material according to any one of claims 1 to 5. A film or sheet made of the polymer material according to any one of claims 1 to 5. Polymeric materials or Ranaru UV (cut) material according to any one of claims 1及至5.

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