JP7192261B2 - protective films and sheets - Google Patents

Description

TECHNICAL FIELD The present invention relates to a protective film and a sheet using the same.

Conventionally, general printed matter does not have high resistance to ultraviolet light, water, and the like. Therefore, in applications such as outdoor decorative sheets and posters that require resistance to these (weather resistance), a transparent protective film is provided on the surface layer for the purpose of protecting printed matter.
As a material for the transparent protective film, in addition to fluorine resin and acrylic resin, which have excellent weather resistance, polyolefin, etc., which is advantageous in terms of cost, is preferably used. Additives are commonly used. For example, hydroxyphenyltriazine compounds have been proposed as UV absorbers that impart excellent weather resistance (Patent Documents 1 and 2). However, in the application of hydroxyphenyltriazine-based UV absorbers to polyolefins, not only does the weather resistance of transparent films differ depending on the structure of the UV absorbers, but white turbidity may also occur, degrading the design of printed matter. In addition, the ultraviolet absorber needs not only a function to protect the printed matter but also a function to suppress deterioration of the protective film itself, but it was difficult to achieve both of these functions while avoiding clouding of the protective film. .

U.S. Patent Application Publication No. 2004/0241111 U.S. Pat. No. 6,191,199

In order to solve the above-mentioned problems, the present invention provides a protective film containing a transparent polyolefin layer that has less white turbidity, which is a factor that impairs design, and has both a function to protect printed matter and a function to suppress deterioration of the protective film itself. The purpose is to provide a sheet using

As a result of intensive studies, the present inventors have found a protective film having a transparent polyolefin resin layer containing a predetermined compounding ratio of ultraviolet absorbers composed of a plurality of hydroxyphenyltriazine compounds having a specific structure, and a sheet using the same. achieves the above-mentioned goals, leading to the present invention.
One aspect of the present invention for solving the above problems is a protective film including at least a transparent polyolefin resin layer, wherein the transparent polyolefin resin layer has a structure represented by the following general formula (1): Contains a hydroxyphenyltriazine-based ultraviolet absorber (UVA-A) and a second hydroxyphenyltriazine-based ultraviolet absorber (UVA-B) having a structure represented by the following general formula (2), and the content of each is , the mass ratio (UVA-A/UVA-B) of the first hydroxyphenyltriazine-based ultraviolet absorber (UVA-A) and the second hydroxyphenyltriazine-based ultraviolet absorber (UVA-B) is 20/80. It is a protective film characterized in that it is in the range of ~80/20.

(In general formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a phenyl group, or an alkoxy group, and at least two of them are alkoxy groups having 8 to 18 carbon atoms, and R4 and R5 are each Each independently represents a hydroxyl group, a methyl group or a hydrogen atom, and each of R6 to R8 independently represents a methyl group or a hydrogen atom.)

（一般式（２）中、Ｒ１は炭素数８から１８のアルコキシ基であり、Ｒ２からＲ５はそれぞれ独立し、水素原子またはメチル基を示す。）

(In general formula (2), R1 is an alkoxy group having 8 to 18 carbon atoms, and R2 to R5 each independently represent a hydrogen atom or a methyl group.)

According to one aspect of the present invention, there is provided a protective film including a transparent polyolefin layer that has little white turbidity that impairs designability and has both a function of protecting printed matter and a function of suppressing deterioration of the protective film itself, and a sheet using the same. provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the cross section of the protective film which concerns on 1st embodiment of this invention. FIG. 4 is a schematic diagram showing a cross section of a decorative sheet according to a second embodiment of the present invention;

[First Embodiment]
As a first embodiment of the present invention, the structure of a protective film 10 having a transparent polyolefin resin layer 11 and a surface protective layer 12 will be described with reference to FIG. However, in each drawing described below, the same reference numerals are given to the parts that correspond to each other, and the description of overlapping parts will be omitted as appropriate. Further, the present embodiment exemplifies the configuration for embodying the technical idea of the present invention, and does not specify the material, shape, structure, arrangement, dimensions, etc. of each part as follows. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

(Transparent polyolefin resin layer)
The protective film 10 according to this embodiment includes a transparent polyolefin resin layer 11 and a surface protective layer 12 formed on one side of the transparent polyolefin resin layer 11, that is, on the upper layer of the transparent polyolefin resin layer 11. .

Examples of the olefin resin constituting the transparent polyolefin resin layer 11 according to the present embodiment include polypropylene, polyethylene, polybutene, and α-olefins (eg, propylene, 1-butene, 1-pentene, 1-hexene, 1 -heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1 - eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1 -pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, etc.) or 2 Copolymers of more than one type, ethylene/vinyl acetate copolymer, ethylene/vinyl alcohol copolymer, ethylene/methyl methacrylate copolymer, ethylene/ethyl methacrylate copolymer, ethylene/butyl methacrylate copolymer, ethylene - Copolymers of ethylene or α-olefins with other monomers, such as methyl acrylate copolymers, ethylene/ethyl acrylate copolymers, and ethylene/butyl acrylate copolymers. Moreover, in order to improve the surface strength of the protective film 10, it is preferable to use highly crystalline polypropylene.

The transparent polyolefin resin layer 11 comprises a hydroxyphenyltriazine-based ultraviolet absorber having a structure represented by the following general formulas (1) and (2), that is, a first hydroxyphenyltriazine-based ultraviolet absorber UVA-A and a second UVA-B, which is a hydroxyphenyltriazine-based ultraviolet absorber, so that the mass ratio of UVA-A and UVA-B (UVA-A/UVA-B) is within the range of 20/80 to 80/20 contains.
In the protection of printed matter with the protective film 10 according to the present embodiment, when the mass ratio of UVA-A and UVA-B (UVA-A/UVA-B) is less than 20/80, the content of UVA-A is Since the amount is too small, discoloration of the pattern layer 32, which will be described later, may increase. In addition, when the mass ratio of UVA-A and UVA-B (UVA-A/UVA-B) exceeds 20/80, the content of UVA-A is too large, and absorption on the short wavelength side becomes weak, Whitening and cracking of the protective film 10 itself may easily occur. Thus, weatherability problems may occur in either case.

UVA-A is preferably a compound represented by the following general formula (3), particularly a compound represented by the following formula (4), 2,4-bis[2-hydroxy-4-(2-ethylhexyloxy)phenyl]- 6-(4-Methoxyphenyl)-s-triazine is more preferred.
UVA-B includes, for example, compounds represented by the following formulas (5), (6), and (7), particularly compounds represented by the following formula (5), 2,4-bis(2,4 -dimethylphenyl)-6-[2-hydroxy-4-(octyloxy)phenyl]-s-triazine is preferred. The octyloxy group of the compound may contain both linear and branched chains.

In general formula (1), R1 to R3 each independently represent a hydrogen atom, a methyl group, a phenyl group, or an alkoxy group, and at least two of them are alkoxy groups having 8 to 18 carbon atoms, and R4 and R5 are Each independently represents a hydroxyl group, a methyl group or a hydrogen atom, and each of R6 to R8 independently represents a methyl group or a hydrogen atom.

In general formula (2), R1 is an alkoxy group having 8 to 18 carbon atoms, and R2 to R5 each independently represent a hydrogen atom or a methyl group.

In general formula (3), R1 and R2 are alkoxy groups having 8 to 18 carbon atoms, R3 is an alkoxy group having 1 to 4 carbon atoms, R4 is a hydroxyl group, and R5 to R8 are hydrogen atoms.

The amount of hydroxyphenyltriazine-based ultraviolet absorbers, that is, UVA-A and UVA-B is not particularly limited, and various conditions such as the thickness of the transparent polyolefin resin layer 11, the adhesive layer 20 and the substrate 30 described later. Although it is appropriately set according to the formula, it is usually in the range of 0.1 parts by mass or more and 2 parts by mass or less with respect to 100 parts by mass of the olefin resin. If the amount of the hydroxyphenyltriazine-based ultraviolet absorber is less than 0.1 parts by mass, it may not be possible to impart sufficient weather resistance to the transparent polyolefin resin layer. Further, when the amount of the hydroxyphenyltriazine-based ultraviolet absorber exceeds 2 parts by mass, the transparent polyolefin resin layer tends to become cloudy. There may be a problem with the designability of

The transparent polyolefin resin layer 11 has an average absorbance of 0.5 or more in the wavelength range of 250 nm or more and 400 nm or less, and a value obtained by dividing the absorbance at 370 nm by the absorbance at 280 nm is in the range of 0.20 or more and 0.9 or less. may be in
If the average absorbance in the wavelength range of 250 nm or more and 400 nm or less is less than 0.5, the later-described pattern layer 32 may be discolored and the transparent polyolefin resin layer 11 may deteriorate in weather resistance. Moreover, when the value obtained by dividing the absorbance at 370 nm by the absorbance at 280 nm is less than 0.20, the pattern layer 32 may be discolored. Moreover, when the value obtained by dividing the absorbance at 370 nm by the absorbance at 280 nm exceeds 0.9, the weather resistance of the transparent polyolefin resin layer 11 may deteriorate.

If necessary, the transparent polyolefin resin layer 11 may contain various additives such as other ultraviolet absorbers, heat stabilizers, light stabilizers, antiblocking agents, catalyst scavengers, colorants, light scattering agents, gloss modifiers, and the like. agents may be added.
Examples of other UV absorbers include, for example, 2-[2-hydroxy-4-(2-ethylhexyloxy)phenyl]-4,6-dibiphenyl-s-triazine, 2-(5-chloro-2H- benzotriazol-2-yl)-6-tert-butyl-4-methylphenol, 2-(5-chloro-2-benzotriazolyl)-6-tert-butyl-p-cresol and the like.

The transparent polyolefin resin layer 11 preferably contains a hindered amine light stabilizer for improving weather resistance. Examples of the hindered amine light stabilizer include 2-(3,5-di-tert-butyl-4 -hydroxybenzyl)-2'-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl), bis(1,2,2,6,6-pentamethyl-4-piperidyl) Known materials such as sebacate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate can be used.
The amount of the hindered amine light stabilizer compounded is preferably in the range of 0.1 to 5 parts by mass, more preferably 0.3 to 3 parts by mass, per 100 parts by mass of the transparent polyolefin resin. is within the range of If the amount of the hindered amine light stabilizer added is less than 0.1 part by mass, the effect of improving the weather resistance is not sufficiently exhibited, and if it exceeds 5 parts by mass, the hindered amine light stabilizer bleeds out, resulting in deterioration of the design and the adjacent layer. Possibility of causing poor adhesion with is increased.

The method for producing the transparent polyolefin resin layer 11 is not particularly limited, and ordinary methods such as calendar film formation and extrusion film formation are used, and the above-mentioned olefin resin, hydroxyphenyltriazine-based ultraviolet absorber and various additives are used. A transparent polyolefin resin layer can be deposited.
The transparent polyolefin resin layer 11 may be provided with unevenness on its surface in order to impart designability. Examples of the method for providing unevenness include a method in which a transparent polyolefin resin film is extruded and then hot embossed, and a method in which cooling rolls provided with unevenness are used to perform extrusion and embossing at the same time.

(Surface protective layer)
The surface protective layer 12 according to the present embodiment is a layer provided to impart functions such as weather resistance, scratch resistance, stain resistance, and designability to the protective film 10 . The material constituting the surface protective layer 12 is not particularly limited, and for example, it can be appropriately selected and used from resin materials such as urethane, acrylic, acrylic silicon, fluorine, and epoxy resins.
The surface protective layer 12 may optionally contain various additives such as ultraviolet absorbers, heat stabilizers, light stabilizers, anti-blocking agents, catalyst scavengers, colorants, light scattering agents and gloss modifiers. You may As the ultraviolet absorber and the light stabilizer, for example, those applied to the above-described transparent polyolefin resin layer 11 can be used.

The method of forming the surface protective layer 12 is not particularly limited. The surface protective layer 12 may be formed by curing by a method suitable for the material, such as heat curing or ultraviolet curing.
The surface protective layer 12 may be provided after the transparent polyolefin resin layer 11 is bonded to the base material 30 described below.

[Second embodiment]
As a second embodiment of the present invention, a configuration in which the protective film 10 according to the first embodiment and the base material 30 are joined to form a decorative sheet 40 will be described with reference to FIG.
The decorative sheet 40 is constructed by bonding the protective film 10 comprising the surface protective layer 12 and the transparent polyolefin resin layer 11, that is, the protective film 10 according to the first embodiment, to the substrate 30 via the adhesive layer 20. . Note that FIG. 2 shows a decorative sheet 40 in which the transparent polyolefin resin layer 11 provided on the protective film 10 and the pattern layer 32 provided on the base material 30 to be described later are bonded via the adhesive layer 20 .

(Original fabric)
The base material 30 includes a raw fabric 31 and a pattern layer 32 provided on one side of the raw fabric 31 .
Examples of raw material 31 include paper such as thin paper, titanium paper, and resin-impregnated paper, synthetic resin such as polyethylene, polypropylene, polybutylene, polystyrene, polycarbonate, polyester, polyamide, ethylene-vinyl acetate copolymer, polyvinyl alcohol, and acrylic. , or foams of these synthetic resins, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-butadiene copolymer rubber, styrene-isoprene-styrene block copolymer rubber, styrene-butadiene-styrene block copolymer It can be arbitrarily selected from rubber such as rubber and polyurethane, organic or inorganic non-woven fabric, synthetic paper, metal foil such as aluminum, iron, gold and silver.
The original fabric 31 may be provided with, for example, a primer layer (not shown) on one or both sides of the original fabric 31 in order to supplement the adhesion with the layers adjacent to the original fabric 31, or may be subjected to corona treatment, plasma treatment, Surface treatments such as ozone treatment, electron beam treatment, ultraviolet treatment, and dichromic acid treatment may be applied.

(picture layer)
The pattern layer 32 is, for example, a pattern printed on the raw fabric 31 using ink. The ink used to form the pattern layer 32 may contain a binder, and examples of the binder include nitrocellulose, cellulose, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyurethane, acrylic, and polyester. It can be used singly or appropriately selected from among modified products. These may be water-based, solvent-based, or emulsion-type, and may be either one-liquid type or two-liquid type using a curing agent.
As a method of curing the ink used for forming the pattern layer 32, there is a method of curing the ink by irradiation with ultraviolet rays, electron beams, or the like. Among them, the most common method is to use urethane-based ink and cure it with isocyanate.

In addition to these binders, the ink used to form the pattern layer 32 contains various additives such as pigments, dyes, and other coloring agents, extender pigments, solvents, light stabilizers, and the like, which are contained in ordinary inks. It is Examples of highly versatile pigments include condensed azo, insoluble azo, quinacridone, isoindoline, anthraquinone, imidazolone, cobalt, phthalocyanine, carbon, titanium oxide, iron oxide, and pearl pigments such as mica.
The method of providing the pattern layer 32 is not particularly limited, and ordinary printing methods such as gravure printing, offset printing, screen printing, flexographic printing, and ink jet printing can be used.

The method of bonding the protective film 10 to the substrate 30 is not particularly limited, and various lamination methods such as heat lamination, extrusion lamination, dry lamination, and sand lamination are used as necessary, for example, via the adhesive layer 20. be able to.
The adhesive layer 20 is not particularly limited. For example, a material that is appropriately selected from resin materials such as urethane, acrylic, acrylic silicon, fluorine, and epoxy and is made into an ink is coated with, for example, gravure coat or micro gravure. It is formed using a usual coating method such as coating, comma coating, knife coating, die coating, and the like.
Regarding the thickness of each layer constituting the decorative sheet 40 according to the present embodiment, the original sheet 31 is 20 μm to 150 μm in consideration of printing workability, cost, etc., the adhesive layer 20 is 0.2 μm to 20 μm, and the transparent polyolefin resin layer 11 is is 20 μm to 200 μm, and the surface protective layer 12 is preferably 3 μm to 20 μm. Also, the total thickness of the decorative sheet 40 is preferably within the range of 45 μm to 250 μm.

EXAMPLES The present invention will now be described in detail with reference to examples and comparative examples.
<Example 1>
Obtained by providing a pattern layer (thickness 3 μm) by gravure printing a wood grain pattern on a polyethylene raw fabric (thickness 70 μm) with concealability using two-liquid urethane ink (V180; manufactured by Toyo Ink Co., Ltd.). A resin composition shown below was extrusion-laminated to a substrate having a thickness of 80 μm through an adhesive for dry lamination (Takelac A540; manufactured by Mitsui Chemicals, Inc.) (thickness: 2 μm) to form a transparent resin layer, that is, a transparent polyolefin resin. formed a layer. Furthermore, as a surface protective layer, a two-liquid curing polyurethane resin layer composed of acrylic polyol (a copolymer of methyl methacrylate and 2-hydroxy methacrylate) and a curing agent (a nurate form of hexamethylene diisocyanate) was coated and formed (layer thickness: 8 μm). 1 cosmetic sheet was obtained.

(resin composition)
・Transparent homopolypropylene resin (Prime PP; Prime Polymer Co., Ltd.)
... 99 parts by mass Light stabilizer (tinuvin XT55; BASF Japan Co., Ltd.)
... 0.5 parts by mass UVA-A (Tinosorb S; (formula (4) below), BASF Japan Co., Ltd.)
... 0.075 parts by mass · UVA-B (Cyasorb 1164; (Formula (5) below), Sun Chemical Co., Ltd.)
... 0.175 parts by mass Mass ratio (UVA-A/UVA-B) = 30/70
The blending amounts of UVA-A and UVA-B were calculated as parts by mass with respect to 99 parts by mass of the transparent homopolypropylene resin and 0.5 parts by mass of the light stabilizer.

<Example 2>
Except that the UVA-A content of the resin composition in Example 1 was 0.125 parts by mass and the UVA-B content was 0.125 parts by mass (UVA-A/UVA-B = 50/50) A decorative sheet of Example 2 was obtained in the same manner as in Example 1.
<Example 3>
Except that the content of UVA-A in the resin composition in Example 1 was 0.175 parts by mass and the content of UVA-B was 0.075 parts by mass (UVA-A/UVA-B = 70/30) A decorative sheet of Example 3 was obtained in the same manner as in Example 1.
<Example 4>
Except that the UVA-A content of the resin composition in Example 1 was 0.085 parts by mass and the UVA-B content was 0.085 parts by mass (UVA-A/UVA-B = 50/50) A decorative sheet of Example 4 was obtained in the same manner as in Example 1.

<Comparative Example 1>
Except that the UVA-A content of the resin composition in Example 1 was 0.025 parts by mass and the UVA-B content was 0.225 parts by mass (UVA-A/UVA-B = 10/90) A decorative sheet of Comparative Example 1 was obtained in the same manner as in Example 1.
<Comparative Example 2>
Except that the UVA-A content of the resin composition in Example 1 was 0.225 parts by mass and the UVA-B content was 0.025 parts by mass (UVA-A/UVA-B = 90/10) A decorative sheet of Comparative Example 2 was obtained in the same manner as in Example 1.

<Comparative Example 3>
In Example 1, UVA-A of the resin composition was replaced with (ADEKA STAB LA-F70; formula (8) below, ADEKA Corporation), and the content of the replaced resin composition was 0.085 parts by mass, A decorative sheet of Comparative Example 3 was obtained in the same manner as in Example 1, except that the content of UVA-B was changed to 0.195 parts by mass. Neither UVA-A nor UVA-B falls under the following formula (8).
The blending amount of ADEKA STAB LA-F70 was calculated as parts by mass for 99 parts by mass of the transparent homopolypropylene resin and 0.5 parts by mass of the light stabilizer.

<Comparative Example 4>
In Example 1, the content of UVA-A in the resin composition was 0.140 parts by mass, UVA-B was replaced with (TINUVIN 1600; the following formula (9), BASF Japan Ltd.), and the replaced resin A decorative sheet of Comparative Example 4 was obtained in the same manner as in Example 1, except that the content of the composition was changed to 0.100 parts by mass. Neither UVA-A nor UVA-B corresponds to the following formula (9).
The amount of Tinuvin 1600 was calculated as parts by mass for 99 parts by mass of the transparent homopolypropylene resin and 0.5 parts by mass of the light stabilizer.

Table 1 below shows the ultraviolet absorbers contained in the transparent resin layers of the above Examples and Comparative Examples. The "average absorbance" shown in Table 1 means the average absorbance in the wavelength range from 250 nm to 400 nm. "A ₃₇₀ /A ₂₈₀ " shown in Table 1 means a value obtained by dividing the absorbance at 370 nm of the transparent resin layer by the absorbance at 280 nm.
<Evaluation>
The decorative sheets obtained in the above examples and comparative examples were evaluated for design and weather resistance by the following methods. The evaluation results are shown in Table 1 below.

a) Designability The appearance of the decorative sheet was visually evaluated according to the following criteria. However, the reference sheet was prepared separately from a sheet containing no ultraviolet absorber in Example 1.
○: No difference in appearance from the reference sheet.
x: A feeling of whiteness is recognized as compared with the reference sheet.

b) Weather Resistance The appearance of the decorative sheet after the accelerated weather resistance test was visually observed, and discoloration of the pattern and change in appearance of the protective film were evaluated according to the following criteria. In the accelerated weather resistance test, an eye super UV tester (SUV-W161; Iwasaki Electric Co., Ltd.) was used, with a black panel temperature of 63 ° C. and an illuminance of 65 mW / cm ² , (20 hours of UV irradiation + 4 hours of condensation) for one cycle. 30 cycles were performed.

(Pattern discoloration)
Evaluation was made in three grades of 3, 2, and 1 in descending order of degree of discoloration.
(Change in protective film appearance)
◯: No difference in appearance is observed.
Δ: Cracks are observed in the transparent resin layer (small degree).
x: Cracks are observed in the transparent resin layer (large degree).

As shown in Table 1, the decorative sheets according to the present embodiment exemplified in the examples have little white turbidity, excellent design properties, and excellent weather resistance.

INDUSTRIAL APPLICABILITY The present invention can be used not only for outdoor sheets such as decorative sheets, posters and signs, but also for indoor sheets such as surface materials for fittings and flooring materials.

10 Protective film 11 Transparent polyolefin resin layer 12 Surface protective layer 20 Adhesive layer 30 Base material 31 Original fabric 32 Pattern layer 40 Decorative sheet

Claims (6)

A protective film containing at least a transparent polyolefin resin layer,
The transparent polyolefin resin layer has a first hydroxyphenyltriazine-based ultraviolet absorber (UVA-A) having a structure represented by the following formula ( 4 ) and a second having a structure represented by the following general formula (2) A hydroxyphenyltriazine-based ultraviolet absorber (UVA-B) is contained, and the respective contents are the first hydroxyphenyltriazine-based ultraviolet absorber (UVA-A) and the second hydroxyphenyltriazine-based ultraviolet absorber. A protective film characterized in that the weight ratio (UVA-A/UVA-B) of (UVA-B) is in the range of 20/80 to 80/20.

(In general formula (2), R1 is an alkoxy group having 8 to 18 carbon atoms, and R2 to R5 each independently represent a hydrogen atom or a methyl group.) The transparent polyolefin resin layer has an average absorbance of 0.5 or more in the wavelength range of 250 nm or more and 400 nm or less, and a value obtained by dividing the absorbance at 370 nm by the absorbance at 280 nm is in the range of 0.20 or more and 0.9 or less. The protective film according to claim 1 , characterized in that: 3. The protective film according to claim 1, wherein the ultraviolet absorber (UVA-B) has a structure represented by the following formula (5).

4. The protective film according to any one of claims 1 to 3 , wherein the transparent polyolefin resin layer further contains a hindered amine light stabilizer. 5. The protective film according to any one of claims 1 to 4 , further comprising a surface protective layer formed on the transparent polyolefin resin layer. A sheet comprising the protective film according to any one of claims 1 to 5 and a base material bonded together.

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