JPS624741A - High brightness reflective material coated film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of sedentary use] The present invention relates to a surface protection film that improves weather resistance and workability and is used in retroactive high-brightness reflective materials.

[Prior art]

A retroreflective sheet in which spherical glass beads are embedded in a transparent resin 741 with good weather resistance and an aluminum vapor deposited layer with high reflection efficiency is provided on the surface is well known. As a further improvement, a layer of spherical glass beads is present between the base sheet and the covering film, with some of the glass beads being exposed, and a layer of spherical glass beads is present between the base sheet and the covering film. A high-brightness reflective material that has an air layer and partially combines a base film and a covering film in a cell shape is available in the United States! li
'Fum 190.178 and 4,025,159.

The performance required of the laminated film used for this high-intensity reflective material is excellent transparency and weather resistance.This is because it is used outdoors for road signs and the like. For this purpose, films such as a polymethyl methacrylate film, a polycarbonate film, and a polyethylene terephthalate film can be used as the covering film.

Among these, films made of polymethyl methacrylate have excellent transparency and weather resistance, and are often used. Since the covering film is bonded to cells of 1 to 2 cm and an air layer is provided, if a crack occurs on the film, it is desirable that the crack end only within one cell. For that purpose,
A strong film that is resistant to cracking is required.

In other words, relatively strong tensile strength (550 K9/
It is desirable to use a film material with a strong tear strength (Crn" or higher).

Furthermore, since high-brightness reflective materials are often used outdoors, the coating film is required to have durability at low temperatures.

However, the 'a8E film made of polymethyl methacrylate has poor durability against temperature changes and has low elongation at break, making it difficult and difficult to manufacture films, especially films for high-brightness reflective materials. . On the other hand, polycarbonate films, polyethylene terephthalate films, etc. do not have good weather resistance and cannot be put to practical use.

Therefore, various methods were investigated to improve workability and durability by adding all the rubber components to polymethyl methacrylate thread resin.
Although it is suggested in No. 2-33991 and No. 57-140161, etc., the rubber-containing multi-stage composite made by these methods is used alone, and the T film is used as a coating film for a high-intensity reflective material. Even if this is attempted, the yield strength of the film is low and the elongation at break is high, so cracks tend to occur in the coating film, which is inappropriate. In other words, as a high-brightness reflective film, it has strong tensile strength (350ψj2 or more) and high tear strength (150fr or more), and has superior A7 durability at low temperatures (film elongation at C°C of 5%). above) is desirable.

Therefore, in order to obtain the necessary transparency and elasticity, durability against temperature changes, and appropriate film strength for a tentatively laminated film of a high-intensity reflective material, we conducted extensive research and found that a specific rubber-containing multilayer It has been discovered that by blending a polymer and a hard resin component, it is possible to impart processability and durability, and also to impart strong breaking strength n'ft
-0 [Means for solving the problem] The present invention provides thermoplastic polymers CI) 20 to 20 shown below.
80 parts by weight and rubber-containing polymer [11] a o ~ 20 parts by weight, and the gel content is 10% by weight or more, 51
This relates to a high-brightness reflective material coating film made of a thermoplastic resin composition with a low density, and the thermoplastic polymer [I] is 50 to 100 weight % of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms. At least one other monoethylenically unsaturated monomer copolymerizable with Toko n O to 50X
The rubber-containing polymer [II] is an alkyl group having 1 to 8 carbon atoms. 80 to 100 parts by weight of an alkyl acrylate or alkyl methacrylate (AI) having an alkyl group having 1 to 4 carbon atoms, 0 to 100 parts by weight of another monomer (A2) having a copolymerizable double bond
20 parts by weight, 0 to 10 parts by weight of polyfunctional monomer (A3), and 1 to 5 parts by weight of a grafting father, ζ Innermost layer polymer consisting of # (N, 51 to 100 parts by weight of alkyl methacrylate having 1 to 4 monomers (C1) and another monomer having a double bond capable of copolymerizing 5J (C2)
The innermost layer polymer (C) has a composition of 0 to 49 parts by weight and has a glass transition temperature (Tg) of at least 40°C, and the entire basic structural unit is an interlayer between polymer (A) ffi and polymer (C). As the intermediate layer (D), an alkyl acrylate (Dl) having an alkyl group having 1 to 8 carbon atoms has 10 to 90! Alkyl methacrylate (D,) having an alkyl group having 1 to 4 carbon atoms 90 to 10
High award part, monomer having a copolymerizable double bond (D3)
0 to 20 parts by weight, 0 to 10 parts by weight of polyfunctional monomer (D4), and the total amount of ion parts by weight of (Dl) to (D4) CL1
~5 parts by weight of graft proximal, ? An intermediate layer polymer (DJ't) is a rubber-containing polymer having at least one layer (the intermediate layer may be omitted). By using a specific acrylic polymer for the purpose, it maintains the excellent transparency and weather resistance that are characteristic of acrylic resin.
The aim is to provide a film that has high durability against temperature changes and has good processability. In order to maintain the high tensile strength and tear strength inherent to acrylic resin, the amount of rubber added must be limited.

The rubber component can be measured as gel content, but if this ft exceeds 50% by weight of the molded film, the tensile strength and tear strength of the molded film will decrease, making it unsuitable as a coating film for high-intensity reflective materials. Become.

On the other hand, if the amount of rubber component added is less than 10 weight fIL% in terms of gel content, the durability against temperature changes will decrease, making it unsuitable as a coating film for high-brightness reflective materials that are often used outdoors.

As described above, the amount of rubber component added, indicated by the gel content, should be strictly adjusted to 1:4. In order to adjust the total amount of the rubber component added, the polymer containing alkyl methacrylate e as the main component [resin D] and the rubber-containing polymer [II] are completely blended to form a thermoplastic composition. Rubber-containing 1 coalescence [f
If a film for a high-intensity reflective material with =9 D is created, it will be difficult to balance fluidity during film molding and film strength, and a good covering film will not be obtained. Therefore, a blending method must be used.

Here, the blend of polymer [I] and rubber-containing polymer [11] has a gel content of 1 (1 m-m
: It should be adjusted to more than 50 degrees and less than 50 degrees.
It is essential that the amount of the polymer [I] is 20 parts or more and not more than 80 parts by weight, and the amount of the rubber-containing polymer [II] is not more than 80 parts by weight and not less than 20 parts by weight.

When the polymer (1) is less than 20 parts of MfI, the gel content is 5
If the amount is 0% by weight or more, the strength of the film molded product will be weakened, which is inappropriate. Furthermore, if 80 parts by weight or more of polymer CD is used, the gel content of the film molded product will be less than 10% by weight, which is inappropriate.

The thermoplastic polymer (1) used in the present invention has 1 carbon number.
Alkyl methacrylate gold having ~4 alkyl groups, obtained by polymerizing monomers containing at least 50 polymers n
Depending on the type of rubber-containing polymer [II] used, the rubber-containing polymer [II] may be appropriately selected so as to satisfy the above requirements.

In this way, physical properties suitable as a coating film for high-intensity reflective materials can only be obtained by blending the alkyl methacrylate polymer (1) with the rubber-containing polymer (II). Union [II] will be explained in detail.

The rubber-containing polymer [n) of the present invention is prepared as follows.

The alkyl acrylate having an alkyl group having 1 to 8 carbon atoms constituting the innermost layer polymer (Al) may be linear or 1-branched, and may be methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2
-Ethylhexyl acrylate, n-octyl acrylate, etc. can be used alone or in combination, but those with a low Tg are more preferred. Further, the alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms may be linear or branched, and methyl methacrylate, ethyl methacrylate, globil methacrylate, butyl methacrylate, etc. may be used alone or in combination. Ru. This alkyl (meta) 7ri17 V-to(At)i'! 80-1
It is used within a range of 00'Ji parts. These alkyls (
It is most preferable to use the same meth)acrylate in all layers, but depending on the final purpose, two or more types of monomers may be mixed and a separate acrylate-t4 may be used to satisfy the present invention.

Other monomers having copolymerizable double bonds (A2)
Preferred examples include acrylic monomers such as lower alkyl acrylate, lower alkoxy acrylate, cyanoethyl acrylate, acrylamide, acrylic acid, and methacrylic acid, which are used in an amount of 0 to 20 parts by weight. Others (styrene within a range not exceeding 20 parts by weight in the Al component,
Alkyl-substituted styrene, acrylonitrile, methacrylonitrile, etc. can be used.

As the polyfunctional monomer (A3), alkylene glycol dimethacrylates such as ethylene glycol dimethacrylate, 1.3 butylene glycol dimethacrylate, 1.4 butylene glycol dimethacrylate and propylene glycol dimethacrylate are preferred; Divinylbenzene, polyvinylbenzene, alkylene glycol diacrylate, and the like can also be used. These monomers work effectively to bridge the layer itself, but do not work on bonding the glabella with other layers. Even if the polyfunctional monomer (A3) is not used at all, as long as the grafting agent (A4) is present,
Although it provides a fairly stable rubber-containing composite composition, it can be used as desired depending on the purpose of addition, such as when hot strength is strictly required, and the range of use is 0 to 10 parts by weight.

As the 10,000-graft cross-agent (A4), copolymerizable α and β
- Allyl, methallyl or crotyl esters of unsaturated carboxylic acids or dicarboxylic acids are preferred, including allyl esters of acrylic acid, methacrylic acid, maleic acid, yohyofumaric acid, and particularly allyl methacrylate exhibits excellent effects. In addition, triallyl cyanurate, triallyl isocyanurate, etc. are also effective. Such graft cross-agents mainly react chemically because the conjugated unsaturated bonds of their esters react much faster than those of allyl, methallyl, or crotyl groups. During this time, a substantial portion of the allyl group, methallyl group, or crotyl group acts effectively during the polymerization of the next layer, providing a graft bond between two adjacent layers.

The fecal dose of the graft cross-agent is extremely important, and the above component (Al
) to 100 parts by weight of the total amount of (A3), α1 to 5
It is used in an amount of 1 part by weight, preferably 15 to 2 parts by weight. If the amount used is less than 0.011 weight parts, the effective amount of graft bonding will be small, resulting in insufficient bonding between layers.

The innermost layer polymer (A) has an individual Tg of 0°C or less,
Preferably, good physical properties are provided when the temperature is below -30°C.

The crosslinked elastic polymer in the rubber-containing polymer composition of the present invention, that is, the innermost layer polymer (the N content is preferably in the range of 10 to 45% by weight).

Outermost layer polymer (C) constituting the rubber-containing polymer of the present invention
is involved in distributing superiority, moldability, mechanical properties, etc. to the polymer composition, and all of these components (
As the component 01) and the component (C2), those equivalent to the component f,<h,) and the component (A2) described above are used. (C1
) component is 51~1001fjk part, (C2) component is 0~
Each is used in a range of 49 parts by weight.

In addition, the Tg of the outermost layer polymer (C) alone is 40°C or higher, preferably 60°C in order to obtain excellent solvent resistance and water whitening resistance.
The temperature must be above ℃.

The outermost layer polymer in the rubber-containing polymer (the content of Q is usually 1
0 to 80% by weight, preferably 40 to 60% by weight.

The rubber-containing polymer of the present invention has the above-mentioned innermost layer polymer (N) and outermost layer polymer (C) as basic structural units, and further comprises the innermost layer polymer (N) and the outermost layer polymer (C) as basic structural units,
10 to 90 parts by weight of an alkyl acrylate (DB) having an alkyl group having 1 to 8 carbon atoms between the A3 layer and the polymer (C) layer, and 90 to 10 parts by weight of an alkyl methacrylate (Dl) having an alkyl group having 1 to 4 carbon atoms. 'x parts, other monomers having a copolymerizable double bond (Dl) 0 to 201 lid part,
Polyfunctional monomer (Da) 0 to 10 parts by weight and (DB)
An intermediate layer (in which O or at least one layer is arranged) is composed of 11 to 5 parts by weight of a grafting agent based on 100 parts by weight of the total amount of (D4).

Here, the components (Dl) to (D4) and the graft cross-agent (D6) are the same as the components used in the innermost layer polymer (AJ). Crossing agents are essential for tightly bonding the chromophoric layers and obtaining superior properties.

The content of the intermediate layer (D) in the rubber-containing polymer of the present invention is preferably 5 to 35% by weight; if it is less than 5% by weight, it will not lose its function as an intermediate layer, and if it exceeds 35% by weight, the final weight will be This may be undesirable as it may upset the balance of the fusion.

When producing the rubber-containing polymer of the present invention, the emulsion particle size of the final polymer is not particularly limited, but is approximately 800 to 2000A, preferably 1000 to 16
The most balanced zero-order structure can be obtained in the range of 00A.

Note that there are no particular restrictions on the surfactant, catalyst, etc. used during production, and additives such as anti-breathing agents and lubricants are added as necessary for salting out treatment.

The most suitable method for producing a rubber-containing polymer is a sequential multi-stage polymerization method using an emulsion polymerization method, but it is not particularly limited to this method. For example, after emulsion polymerization, the outermost layer polymer (C) is A suspension polymerization method can also be employed during polymerization.

All the usual blending methods can be used to blend the above rubber-containing polymer (n)''k polymer [I], and antioxidants, ultraviolet absorbers, fillers, and pigments may be added as necessary. etc. are added.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to examples, and the abbreviations used in the examples are as follows.

Methyl methacrylate MMA butyl acrylate BuA butyl methacrylate) 8MA2ethylhexyl acrylate ZJCHAI, 3-butylene dimethacrylate)
BD allyl methacrylate
AMA Methyl Acrylate MA Cumene Hydroperoxide OHP Sodium Formaldehyde Sulfoxylate) SF
B Styrene St polymethyl methacrylate PMMA polystyrene
Method for measuring pst gel content J1st According to K-6588, a specified amount of the entire thermoplastic polymer was sampled and heated at 25°C for 48 hours with methyl ethyl ketone (hereinafter referred to as
(abbreviated as MllThK), swelled, pulled out, wiped off the attached MKK, measured its weight, and then dried in a vacuum dryer to remove all MKK.
Read the absolute dry weight that has reached a constant weight, and calculate the gel content using the following formula.

叉、Used in the main text /? ! The TgU of the rmx combination, for example, is calculated from the Tg values of each component described in the Bolimano book using the commonly known FOXO formula % formula %.

Furthermore, the total light transmittance and tear strength of the films in the examples were determined by the following methods.

Total light transmittance V was measured using an integrating sphere haze meter in accordance with ASTM D 1005-trl.

Tear strength: Measured according to TISP-8116 using the Nille-Mendorff method with a cutting depth of 2+am.

Examples 1-5. Comparative Examples 1 to 2 250 parts of ion-exchanged water, 2 parts of ester soda salt of sulfosuccinic acid, and 0.05 parts of 8FB were placed in a polymerization container equipped with a cooler, and after stirring under nitrogen, the innermost layer polymer shown in Table 1 (N
A mixture of each monomer and 10 parts of OHPα was charged. 7
After raising the temperature to 0°C, maintain the temperature for 60 minutes to prepare the polymer (A).
Completed the polymerization of Friend.

Subsequently, a mixture of each monomer for the intermediate layer (I) shown in Table 1 is added and reacted, and finally the outermost layer polymer (C) as shown in Table 1 is made of monomers having various compositions. The polymer mixture was completely added and reacted to form an outermost layer polymer (○) having a different 'rg. The final particle size of each sample was in the range of 1000 to 1500A.

The obtained polymer emulsion gold was salted out using 5 parts of calcium chloride per 100 parts of the polymer, washed, and dried.

50 parts of the rubber-containing polymer of Experiment 1 was mixed with polymer CI) M
MA/MA combined East I [MA/MA=99 parts 1 weight ratio, 7sp/c=060 C=[L10f/dt] of 5
0 parts and blend using a Henschel mixer.

Extruder with vent? The above mixture was shaped into pellets. The obtained n-liter pellets were dried at 80°C day and night, and T-
A die was used to form a film having a thickness of 0.10 parts. The moldability is extremely good, and the obtained film has excellent transparency and high impact strength.

Similarly, for each rubber-containing polymer in Experiments 2 to 5,
All films as shown in Table 2 were prepared by blending 0 parts. The tensile strength, tear strength, and elongation at low temperatures of this film were measured, and the results shown in Table 2 were obtained. However, when a film made only of methyl methacrylate yarn as shown in Comparative Example 1 was used, the yield strength and tear strength of the film showed good results. 9, which was found to be defective and lacking in durability at low temperatures.

In addition, when a film made only of the rubber-containing polymer shown in Comparative Example 2 is used, the yield strength of the film decreases and the tear strength of the film becomes poor, making it impossible to put it to practical use. Examples 6-10. Comparative Examples 3-4 Rubber-containing polymer i of Experiments 1 and 5 synthesized in the previous examples, MMA/MA copolymer (MMA/MA=94/6
1! Quantity ratio, ηsp/c=α550=Q, 10 dL/
fr) in various proportions to obtain resin compositions. The physical properties of the film obtained from this composition were measured, and the results shown in Table 3 were obtained.

If the amount of the rubber-containing polymer is less than 20 parts, the elongation of the film at 0° C. will be insufficient and the durability at low temperatures will be insufficient. On the other hand, if it exceeds 80 parts, the tear strength decreases and it becomes impossible to achieve the strength required for a coating film for a high-brightness reflective material.

The rubber-containing polymer used in Experiment 3 had a refractive index that matched the refractive index of the MMA polymer as the matrix resin, and had extremely good transparency, making it possible to form a coating film with excellent weather resistance. .

Examples 11-12 Rubber-containing polymer 6 was totally synthesized in the same manner as in Experiment 3, except that BMA'j was used instead of MMA in the rubber-containing polymer of Experiment 3 described above.

Similarly, rubber-containing polymer 7 was synthesized in the same manner as in Rubber Experiment 5, except that 2 ERA was used instead of BuA in Experiment 3.

50 parts by weight of each of these rubber-containing polymers were blended with 50 parts by weight of the MMA/MA copolymer used in Example 1 to obtain a resin composition.

A film with a thickness of 1m was made from these resin compositions,
The strength of all the films was measured, and the results shown in Table 4 were obtained, indicating that in all cases, the film was excellent as a coating film for a high-brightness reflective material.9.

Table 4 [Effects of the Invention] As detailed above, the film obtained by the present invention has excellent transparency, strong tensile strength, high tear strength, and excellent durability at low temperatures. By coating the surface of the high-brightness reflective material, it is possible to provide a high-brightness reflective material with higher performance than PC◎

Claims (1)

[Scope of Claims] Consisting of 20 to 80 parts by weight of the thermoplastic polymer [I] shown below and 80 to 20 parts by weight of the rubber-containing polymer [II], and having a gel content of 10% by weight or more and 50 parts by weight % of a thermoplastic resin composition. Thermoplastic polymer [I] 50 to 100% by weight of alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms and at least one other monoethylenically unsaturated monomer copolymerizable with the same.
Polymer rubber-containing polymer consisting of 0 to 50% by weight of species [II] 80 to 100 parts by weight of alkyl acrylate having an alkyl group having 1 to 8 carbon atoms or alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms (A_1) , 0 to 20 parts by weight of other monomers having copolymerizable double bonds (A_2), 0 to 10 parts by weight of polyfunctional monomers (A_3), and the total amount of (A_1) to (A_3) Innermost layer polymer (A) consisting of 0.1 to 5 parts by weight of graft cross-agent (A_4) per 100 parts by weight, alkyl methacrylate having 1 to 4 carbon atoms (C_1) 51
An outermost layer polymer consisting of ~100 parts by weight and 0 to 49 parts by weight of another monomer (C_2) having a copolymerizable double bond, and having a glass transition temperature (Tg) of at least 40°C. C) is the basic structural unit, and an intermediate layer (
As D), 10 to 90 parts by weight of alkyl acrylate (D_1) having an alkyl group having 1 to 8 carbon atoms, 1 carbon number
90 to 10 parts by weight of alkyl methacrylate (D_2) having ~4 alkyl groups, 0 to 20 parts by weight of other monomer (D_3) having a copolymerizable double bond, polyfunctional monomer (D_4) 0 to 10 parts by weight, and 100 parts by weight of the total amount of (D_1) to (D_4),
A rubber-containing polymer having 0 or at least one layer of a copolymer having a composition of 0.1 to 5 parts by weight of a graft cross-agent (D_5).