JPH0330945A - Acrylic resin laminated sheet for front panel of automatic vending machine - Google Patents

Abstract

PURPOSE:To enhance impact resistance, rigidity, hardness, transparency, weatherability and thermal moldability by providing a highly weatherproof transparent thermoplastic resin layer to the single surface of a specific impact- resistant acrylic resin layer. CONSTITUTION:A composition wherein the mean particle size of the elastomeric polymer used in an impact-resistant acrylic resin is 0.15-0.40mum and the content thereof in said impact-resistant acrylic resin is 8-40wt.% has capacity excellent in impact resistance, rigidity, hardness and transparency. The impact-resistant acrylic resin is prepared by containing the elastomeric polymer in a general acrylic resin and the general acrylic resin means a polymer of methyl methacrylate or the like and the elastomeric polymer means an acrylic ester polymer. As a transparent thermoplastic resin excellent in weatherability, a general acrylic resin or fluoplastic is designated and the transparent thermoplastic resin is laminated to a substrate part composed of an impact-resistant acrylic resin.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an impact-resistant material developed for use in vending machine front panels that has excellent impact resistance, rigidity, weather resistance, transparency, etc., and is thermoformable. This invention relates to an acrylic resin laminated sheet.

[Conventional technology] Acrylic resin is a thermoplastic resin with excellent transparency, beauty, weather resistance, printing properties, etc. Taking advantage of these properties, it can be used for signage,
It is widely used in many fields such as displays, lighting covers, exteriors, domes, and stationery.

In these applications, general acrylic resin plates have long been used for vending machine front panels, but recently, vending machines have become larger, front panels have been drawn and formed, and molded products have become more complex in shape. In response to this trend and the problem of the front panels of vending machines installed in cars being intentionally damaged, there is a strong demand for improving the impact strength of these front panels.

For this reason, 1.7 impact resistant acrylic resins have recently been increasingly used for the front panels of vending machines.

However, this impact-resistant acrylic resin usually has an acrylic elastomer polymer added as a modifier to the general acrylic resin in order to increase its impact strength; On the other hand, a problem has arisen in that the properties inherent to general acrylic resins, such as rigidity, strength, hardness, weather resistance, and transparency, deteriorate.

In the case of vending machine front panels, it is true that improving impact resistance strength is one of the biggest challenges, but it is also necessary to minimize the deterioration of the physical properties mentioned above and make them similar to those of general acrylic resins. However, so far, nothing has been obtained that satisfies these requirements (1).

[Problems to be Solved by the Invention] The problem of the present invention is to solve the above-mentioned problems of conventional impact-resistant acrylic resins, and to provide an impact-resistant acrylic resin laminate that has excellent properties especially for use in vending machine front panels. It's where the seats are provided.

[Means for Solving the Problems] In order to solve the above problems, the present inventors, as a result of intensive research, have solved the above problems by providing a highly weather-resistant transparent thermoplastic resin layer on one side of a specific impact-resistant acrylic resin layer. The inventors have found that the object can be achieved and have arrived at the present invention.

In other words, the present invention consists of a substrate made of an impact-resistant acrylic resin containing 8 to 40% by weight of an elastic polymer with an average particle size of 0.15 to 0.40 μm, and a highly weather-resistant transparent thermoplastic resin. The present invention provides an acrylic resin laminated sheet for a vending machine front plate, which is made up of a laminated portion.

The impact-resistant acrylic resin used in the present invention is made by dispersing an elastic material that is rubber-like at room temperature in the form of particles in a continuous resin phase mainly composed of methyl methacrylate. As a result, it was found that it is important to specify the particle size and content in order to exhibit excellent properties as a vending machine front panel. That is, the particle size of the elastic polymer affects the impact strength and transparency of the impact resistant acrylic resin, and as the particle size increases, the impact strength increases but the transparency decreases. On the other hand, the content of the elastomer polymer affects the impact resistance, rigidity, hardness, weather resistance, etc. of the impact resistant acrylic resin, and as the content increases, the impact resistance increases, but the rigidity, hardness, weather resistance There is a tendency for this to decline.

Vending machines are often installed outdoors, exposed to sunlight, on roadsides with a lot of exhaust gas and dust, and because they are unmanned stores, the general public is reluctant to purchase them due to their beauty and cleanliness. It is required to stimulate motivation, and the physical properties of the front panel used for this purpose are important. In this sense, the required characteristics of the vending machine front plate must be excellent in impact resistance, rigidity, hardness, transparency, and weather resistance. As a result of detailed examination by the present inventors, it was found that the average particle size of the elastic polymer used for impact-resistant acrylic resin is 0.15 μm or more and 0.40 μm.
or less, and the content of the elastic polymer in the impact-resistant acrylic resin is 8,000 ω% or more and 40% by weight or less, which has excellent impact resistance, rigidity, hardness, and transparency. I found out that it has. If the average particle size of the elastic polymer is smaller than 0.15 μm, the impact resistance of the impact-resistant acrylic resin will be reduced, while if it is larger than 0.140 μm, the haze of the impact-resistant acrylic resin will increase and the transparency will decrease. descend. Note that preferably the average particle size is 0.
It is 20 μm or more and 0.30 μm or less. In addition, if the content of the elastic polymer in the impact-resistant acrylic resin is less than 8% by weight, the sweat impact resistance of the impact-resistant acrylic resin will decrease, while if it is more than 40% by weight, the impact-resistant resin will The rigidity, hardness, transparency, and weather resistance of

In addition, the more preferable content is 10 mm% or more and 30 mm%
It is as follows.

The impact-resistant acrylic resin of the present invention is a general acrylic resin containing an elastic polymer as shown in item 1 above.
General acrylic resin is a copolymer made by copolymerizing 100% methyl methacrylate and methyl methacrylate with alkyl acrylates such as methyl acrylate-1~, delacrylate, propyl acrylate, and butyl acrylate. say.

The elastomer polymer referred to in the present invention refers to an acrylic ester polymer, and specific examples thereof include those containing butyl acrylate, 2-ethylhexyl acrylate, etc. as main components, and representative examples thereof include butyl acrylate, etc. It is a particulate elastic body in which a grafted rubber elastic component of fulkyl acrylate and styrene and a hard resin layer made of methyl methacrylate and/or a copolymer of methyl methacrylate and alkyl acrylate form a multilayer core-shell structure.

The impact-resistant acrylic resin may contain ultraviolet absorbers, antioxidants, stabilizers, and coloring dyes as long as they do not impair transparency.

Another important point in the present invention is that the impact-resistant resin is used as a substrate and a transparent thermoplastic resin with excellent weather resistance is laminated on one side of the substrate. As a result, as mentioned above, when the substrate part contains an elastic polymer, weather resistance as well as mechanical properties deteriorate, whereas transparent thermoplastic material with excellent weather resistance is used on top of the substrate part. This is because by laminating the resin, deterioration in weather resistance of the substrate portion can be completely prevented. Transparent thermoplastic resins with excellent weather resistance used here include general acrylic resins, fluororesins, etc.
In terms of practicality such as adhesion, general acrylic resins are made of 100% methyl methacrylate, and methyl methacrylate is the main component, and alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate are copolymerized with this. Among the fluororesins, polyvinylidene fluoride (PVDF) is preferred.

These transparent thermoplastic resins with excellent weather resistance need to be laminated on the substrate portion made of the above-mentioned impact-resistant acrylic resin, and the thickness of the laminated portion may be 5 to 100 μm. If the thickness is 5 μm or more, it is sufficient to prevent weather resistance and can sufficiently cover the elastic particles of the substrate portion. In addition, the laminated part contains an ultraviolet absorber,
Antioxidants, other stabilizers, antistatic agents, and coloring dyes may be added as long as they do not impair transparency.

Also, the thickness of the laminated sheet is 17M for the front panel of a vending machine.
to 5M, and the commonly used thickness is 2# to 3IM1.

Coextrusion (Co
There are two methods: extrusion method and lamination method. The coextrusion method is superior in that the fluidity of both layers can be matched and made uniform during lamination, resulting in good adhesion between the two layers and similar molding distortion. Co-extrusion is carried out using two regular extruders, and the impact-resistant acrylic resin used as the substrate is 40. φ, 60m
IIφ, 90mφ, etc., and the weather-resistant transparent thermoplastic resin of the laminated part is smaller than 30mm. φ,ttom
An extruder of mφ, 50mφ, etc. is used.

The thickness of the laminated portion of the laminated sheet and the substrate portion are controlled by the extrusion amount of the two extruders and the roll clearance of the polishing roll at the exit of the extruder. If the thickness of the laminated part and the entire layer of the laminated sheet is 1 m or more, check the thickness with a caliper. If the thickness is 1 m or less, check the cross section of the sheet using a differential interference microscope or a commercially available film thickness cutter (for example, Bick Mallinckrodt Co., Ltd.). (West Germany) PIG Llniversal
(Film thickness for dry film)).

It is important to match the fluidity of the resins in the substrate part and the laminated part, and this can be specifically done by adjusting the temperature of the extruder.

The laminating method can be such that a film made of general acrylic resin is supplied at a polishing (calending) roll section at the exit of an extrusion type gouer, and is overlapped with the resin extruded from an extruder at the roll section. In this case, the technical points are prevention of air intrusion during overlapping and improvement of adhesion by adjusting roll temperature, etc.

The use of the laminated sheet of the present invention is iI impact resistance rigidity, hardness,
Because it has excellent transparency, weather resistance, and thermoformability, it is particularly effective as a front plate of a vending machine that is used outdoors as a transparent molded plate for a long time. The laminated sheet of the present invention can also be used for signboards, displays, automobile visors, etc. for purposes similar to vending machine front panels.

[Example] The present invention will be specifically explained below using Examples and Comparative Examples.

The evaluation and test methods used in each example and comparative example are as follows.

(1) Evaluation of impact resistance: A falling ball impact test was adopted, and the equipment was a DuPont impact tester manufactured by Toyo Seiki Seisakusho. The impact strength was determined from the height at which 50% or more of the F was broken in 12 tests, and was used as the impact strength of the sample.

(2) Cutting rate: This was done in accordance with JIS 7203.

(3) Evaluation of Rockwell hardness: Performed according to JIS 7202.

(4) Transparency 1i11' (iih: JIS
The total light transmittance and haze (@value) were measured according to K7105.

(5) Evaluation of weather resistance: Using the Linshine Weather-Ometer (hereinafter abbreviated as SWOM) of Suga Test Instruments ■, irradiate the sample at 2000 HR with the laminated surface of the sample as the irradiation surface, and measure the haze (degrees) of the sample at that time. @ Grinding (NDH-) made by Nippon Heavy Industries ■
1001DP).

(6) Evaluation of ripening formability: Vacuum forming was performed in a pen dish shape with a drawing depth of 1100 rI using an ordinary vacuum forming machine, and the appearance was observed and evaluated.

Example of production of elastomer polymer: 6860 rnl of ion-exchanged water and 17.759 ml of sodium dihexyl sulfosuccinate were put into a reactor with an internal volume of 10 fI and equipped with a reflux condenser, and the temperature was raised to 75°C under a nitrogen atmosphere while stirring at a rotational speed of 250 rpm. did. Methyl methacrylate (MMA) 534.69, butyl acrylate (
BA>19.4g, allyl methacrylate (ALMA
) 0.443g and ultraviolet absorber Tinuvin p 0
．． A mixture consisting of 166 g was divided 2:3 by weight,
The former was designated as (Bl), and the latter was designated as (B2). 5 minutes after adding (B1) to the above reactor, 0.0% ammonium persulfate was added.
22 g was added and held for 45 minutes. Next (B2)
was added continuously over 12 minutes, and held for 20 minutes after the addition was completed. The polymer latex thus obtained was cooled to 40°C.

Next, BA 1141g, styrene (3t) 259g
, polyethylene glycol diacrylate (PEGDA)
) (molecular weight 200) 3.64g, ALMA 14.84
A mixture consisting of g and Tinuvin P O,429 was added to the reactor and stirring was continued for 60 minutes. This latex 7
The temperature was raised to 5° C., 1.42 g of ammonium persulfate was added, and the temperature was maintained for 190 minutes. Next, MMA 876.1g, BA
11.54 g, normal octyl mercaptan (n-
A mixture consisting of OM>2.663 and 0.27 g of Dinuhin p was divided 1:1, the former being (B3) and the latter (
B4). Next, (B3) was continuously added to the reactor over a period of 90 minutes. After the addition was completed, the mixture was kept for approximately 60 minutes. Furthermore, after adding 0.18 g of ammonium persulfate to the reactor, (B4) was finally continuously added over 20 minutes, and held for 30 minutes after the addition was completed. Then warm to 95°C for 60
Hold for minutes. The latex obtained in this way was
It was poured into a diluted sodium sulfate solution, salted out and coagulated, then dehydrated and washed repeatedly, and then dried.
An elastic polymer (R1) was obtained. This elastic polymer 2
0% by weight and Delpet LP-1 (copolymer of methyl methacrylate and methyl acrylate) manufactured by Asahi Kasei Corporation 8
After mixing with 0% by weight for 20 minutes in a Henschel Michili, pelletization was carried out at 240° C. using a 30Ill11 vented twin-screw extruder (manufactured by Nakatani Kikai, Type A).

The particle size of the elastomer polymer was changed by changing the emulsifier to, for example, sodium dioctyl sulfosuccinate or by changing the rate of addition of the 7-mers (B1) and (B2) in the same manner as in the production example of the elastomer polymer described above. We were able to synthesize a polymer.

The elastomer polymer thus obtained was dispersed in Delvet LP-1 as described above, and after staining with ruthenic acid, the average particle size was measured using a transmission electron microscope. The results are shown in Table-1.

Table-1 Average particle size of elastic polymer Example-1 Elastic polymer (
R1, average particle size 0.25 μm) and 80 wt. , an extruder with L/D=32 was used, and on the other hand, Delpet 8ON (copolymer of methyl methacrylate and methyl acrylate) manufactured by Asahi Kasei Industries II was placed in the laminated part with a diameter of 30 nm.
Coextrusion was carried out using an extruder with rm and L/D=32. The die is a feed block type and the temperature of the extruder is 2.
Performed at 50-260'C.

The thickness of the laminated sheet was adjusted by the die lip opening degree and the clearance of the polishing roll at the die outlet, and the thickness of the laminated portion was adjusted by the extrusion rate of both extruders. In this way, a laminated sheet with a sheet width of 80C was produced. The thicknesses of the laminated sheet and the laminated portion were 3.0# and 50μ, respectively. The physical properties of the laminated sheet were evaluated using the method described above. The results are shown in Table-2.

Examples-2 to 5, Comparative Examples-1 to 4 The impact-resistant acrylic resin of the substrate part was the same elastic polymer as in Example-1, and the content was between 5% by weight, 8% by weight, and 10% by weight.
Laminated sheets were prepared in the same manner as in Example 1 except for the weight %, 30 weight %, 40 weight %, and 50 Φ weight %, and the physical properties of each were evaluated.

Furthermore, for further comparison, single-layer sheets of Delpet 8ON and impact-resistant acrylic resin containing 20% by weight of the above-mentioned elastic polymer were produced using the extruder for the substrate part of Example-1. , and the respective physical properties were similarly evaluated. These results are shown in Table-2.

The content of the elastic polymer in the substrate is between 8% and 4% by weight.
The physical properties of the 0% by weight laminated sheet are high impact strength, flexural modulus, hardness, and transparency, as well as excellent weather resistance due to the effect of the acrylic resin in the laminated part, and it has a good balance of physical properties. A product suitable for the front panel of a vending machine was obtained.

On the other hand, when the content of the elastic polymer in the substrate part was 5% by weight (Comparative Example-3), the impact strength of the laminated sheet decreased significantly, and when the content of the elastic polymer was 50% by weight ( In Comparative Example 4), the flexural modulus, hardness, and transparency of the laminated sheet were significantly lowered, and all of these problems were problematic for use as a front plate of a vending machine. Furthermore, in the single-layer sheets of Delvet 8ON and impact-resistant acrylic resin (Comparative Example-1°2), the former has problems in impact resistance, and the latter has problems in weather resistance.

Examples-6 to 9, Comparative Examples-5 to 6 Elastic polymers having an average particle size of 0.09 μm to 0.45 μm as shown in Table 1 were added by 20% by weight each to Delpera 1 to 'LP-1''80. A laminated sheet was produced in the same manner as in Example 1, except that a mixture of 1% silica and 1% carbon dioxide was used as the impact-resistant acrylic resin for the substrate part.

The results of each evaluation are shown in Table 3. Laminated sheets with elastic polymer particle diameters of 0.15 to 0.40 μm have excellent physical properties such as impact strength, flexural modulus, hardness, transparency, and weather resistance that cannot be achieved with a single resin layer. It shows balance and provides excellent performance for vending machine front panels. On the other hand, when the particle size of the elastic polymer used for the substrate part is 0.09 or 0.45 μm, there is a problem in impact resistance strength in the former case, and a problem in transparency in the latter case.

[Effects of the Invention] The present invention provides a laminated sheet that has excellent impact resistance, rigidity, hardness, transparency, and weather resistance, as well as good thermoformability, and its use as a front panel for vending machines is further improved. This is expected to increase.

(Margin below)

Claims (1)

[Scope of Claims] 1. A substrate made of an impact-resistant acrylic resin containing 8-40% by weight of an elastic polymer with an average particle size of 0.15-0.40 μm and a highly weather-resistant transparent thermoplastic resin. An acrylic resin laminated sheet for the front panel of a vending machine, which is made up of a laminated part and a laminated part. 2. The acrylic resin laminate sheet for a vending machine front plate according to claim 1, wherein the highly weather resistant transparent thermoplastic resin is a general acrylic resin or polyvinylidene fluoride.