JP5603446B2 - UV-absorbing molded product formed by molding UV-absorbing material - Google Patents

Description

The present invention relates to a molded article made of an ultraviolet absorbing material. More specifically, the molded article 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 near-red region. The present invention relates to a molded article for ultraviolet absorption formed by molding an ultraviolet absorbing (cut) material excellent in light transmittance in an outside light region and excellent in processability to molded articles 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 light and near-infrared light. There has been a strong demand for polymer (resin) materials having excellent properties.

  An ultraviolet absorbing material made of a resin not containing an ultraviolet absorber has already been proposed. Patent Document 2 discloses that a hydrazine-based compound such as hydrazine is 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 restricted 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 various physical properties of ionomers using various metal elements, Ce ion ionomers happened to be in the visible light region and near infrared light region. In the present invention, high light transmittance was exhibited, while on the other hand, in the ultraviolet light region having a wavelength of 350 nm or less, it was found that extremely high light absorptivity was exhibited, and the present invention was completed.

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. certain ultraviolet absorber (cut) material comprising a polymer material having excellent UV absorbing ability processability into molded articles equal formed shape and formed by moldings, in particular, a film made of said material, to provide a sheet .

According to the present invention, an excellent ultraviolet absorbing material comprising a cerium (Ce) ionomer of an ethylene / unsaturated carboxylic acid copolymer is 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, The neutralization degree of the ionomer with cerium (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 composition having excellent ultraviolet absorbing ability of the present invention preferably has a mode in which zinc ion (ZnO) fine powder is further blended with the ionomer.
The present invention also provides a molded product formed by molding the ultraviolet absorbing material, particularly a film or sheet made of the ultraviolet absorbing material.

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.

The spectrophotometric measurement diagram of the product of the present invention and the comparative product film and sheet.

Hereinafter, the present invention will be described in detail and specifically with reference to a partial diagram.
The ultraviolet absorbing material having ultraviolet absorbing ability of the present invention is composed of a cerium (Ce) 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. More specific examples of the alkyl group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 2-ethylhexyl, and isooctyl.
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, particularly 10 to 500 g / 10 at 190 ° C. and 2160 g load (according to JIS K7210). 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 the above, 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.

The ionomer of the present invention is obtained by partially or completely neutralizing the carboxyl group of the ethylene / unsaturated carboxylic acid copolymer with cerium (Ce) ions.
Cerium (Ce) belongs to group 3 of the periodic table, and is one of the lanthanoid elements among the rare earth elements. Oxidation numbers 3 and 4, that is, trivalent or tetravalent ions are known.
In the ionomer of the present invention, cerium is preferably used in a trivalent ion state.

In the ionomer of the present invention, the degree of neutralization of the carboxyl group of the ethylene / unsaturated carboxylic acid copolymer by the cerium (ion) is preferably 10% or more, particularly 30-60, in order to obtain excellent ultraviolet absorption performance. % Is preferred.
Further, the melt flow rate (MFR) of a cerium (Ce) ion ionomer of an ethylene / unsaturated carboxylic acid copolymer at 190 ° C. under a load of 2160 g (according to JIS K7210) is 0.01 to 100 g / 10 min, particularly 0. It is preferable from the viewpoint of imparting strength to a molded product obtained from 1 to 50 g / 10 min.

Next, the method for preparing an ionomer of the present invention will be described by taking as an example the case of preparing the Ce ionomer from an 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 Ce salt powder taking into account the carboxylic acid unit content of the resin, the desired degree of neutralization, etc. The solution, for example, cerium acetate (Ce (CH ₃ COO) ₃ ) powder or an aqueous solution thereof is added and, for example, using a kneading apparatus such as a plastmill single-screw or twin-screw extruder at a temperature of about 100 to 250 ° C., An ionomer material is obtained by kneading at a stirring speed of about 20 to 150 rpm for about 5 to 50 minutes.
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 obtained as described above 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 the Ce ionomer of the present invention is shown in FIG.
The figure shows (1) Ce ionomer (invention product: base resin; ethylene / methacrylic acid copolymer, methacrylic acid content = 15 wt%, MFR = 60 g / 10 min, density 940 kg / m ³⁾ ; (2) Commercially available Zn ionomer (Comparative example product: High Milan H1706 manufactured by Mitsui DuPont), and (3) Zinc oxide in the commercially available Zn ionomer. Transmittance (T:%) for light in the 200 nm to 2200 nm wavelength region of a press sheet (thickness is about 500 μm) composed of a composition containing 1000 ppm of ultrafine particles (average particle size: 20 nm). FIG.

From FIG. 1, Ce ionomer (1) which is the product of the present invention shows light transmittance almost equal to that of commercially available Zn ionomer (2) in the visible light wavelength region and infrared wavelength region, and from the fine ZnO compounding composition (3). Is clearly excellent in light transmittance.
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:
(Double-circle): The transmittance | permeability of the light wavelength of 350 nm, 330 nm, and 300 nm is visible light 5
The transmittance is smaller than 00 nm, and in particular, the transmittance at 300 nm is 0%.
A: The transmittance at a light wavelength of 300 nm is less than 10%.
Δ: The transmittance at a light wavelength of 300 nm is less than 20%.
X: The transmittance | permeability of the 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 | permeability of the light wavelength of 500 nm of visible light region is less than 50%.
Bleed-out characteristics:
○: No change in surface condition is observed even when a 500 μm thick test piece is exposed to an atmosphere of 40 ° C. × 90% RH for 3 months.
X: 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"
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.
Then, using this material, a press sheet having a thickness of 500 μm was produced 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" (reference example)
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. The resulting mixture was kneaded to obtain a Ta ionomer material having a neutralization degree of 30% (that is, 30% of the carboxyl groups of the base resin were neutralized with Ta (ions)).
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"
A press sheet having a thickness of 500 μm was prepared from a commercially available Zn ionomer (High Milan H1706 manufactured by Mitsui DuPont).
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 in Comparative Example 1 was mixed with 0.07 g of ultrafine zinc oxide (ZnO: nanofiller: average particle size of about 20 nm) and kneaded in a lab plast 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 in Table 2, it can be seen that the metal element ions other than Ce and Ta cannot realize the excellent ultraviolet absorption function of the product of the present invention even if it is a metal element of the same group.

1 Inventive Example 1 (Ce ionomer)
2 Comparative Example 1 (Zn ionomer)
3 Comparative Example 2 (ZnO fine particle blend composition)

Claims (8)

An ultraviolet absorbing molded product formed by molding an ultraviolet absorbing (cut) material made of a cerium (Ce) ionomer of an ethylene / unsaturated carboxylic acid copolymer. The molded article for ultraviolet absorption according to claim 1, wherein the ethylene / unsaturated carboxylic acid copolymer has an unsaturated carboxylic acid unit content of 2 to 30% by weight. The molded article for ultraviolet absorption according to claim 1 or 2, wherein the ionomer has a cerium ion neutralization degree of 10% or more. The ultraviolet-absorbing molded article according to any one of claims 1 to 3, wherein the ethylene / unsaturated carboxylic acid copolymer comprises an ethylene / (meth) acrylic acid copolymer. The molded article for ultraviolet absorption according to any one of claims 1 to 4, wherein zinc ion (ZnO) fine powder is further blended with the ionomer. The molded article for ultraviolet absorption according to any one of claims 1 to 5, wherein the light transmittance at a wavelength of 350 to 300 nm is smaller than the light transmittance at a wavelength of 500 nm. The molded article for ultraviolet absorption according to any one of claims 1 to 5, wherein the light transmittance at a wavelength of 300 nm is 0%. An ultraviolet absorbing film or sheet comprising the ultraviolet absorbing (cut) material according to any one of claims 1 to 7.

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