CA1282287C

CA1282287C - Marking material

Info

Publication number: CA1282287C
Application number: CA000497556A
Authority: CA
Inventors: Makoto Sasaki
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1984-12-14
Filing date: 1985-12-13
Publication date: 1991-04-02
Anticipated expiration: 2008-04-02
Also published as: KR870700085A; JPH0431396B2; JPS61141477A; WO1986003767A1; EP0203996A1; KR930010441B1

Abstract

MARKING MATERIALS

Abstract A marking material comprising an adhesive layer on at least one surface of a base, the base comprising a continuous porous plastic film having an average pore size of 0.2 to 50 µm an air permeability of 2 to 120 sec/100 cc and a thickness of at least 20 µm.

Description

1~8~'~87 Technical Field This invention relates to an improvement in marking materials for decoration and marking used by application to outdoor signs, gasoline tanks for two-wheeled vehicles~ vehicular body surfaces and the like. More particularly, this invention relates to an improvement in air-permeable marking materials without causing peeling or blistering, etc. even on evolution of gases (outgassing) from the adherend to be applied.
In drawings which illustrate various embodiments of the invention and compare them with prior art;
Figure 1 is a sectional view showing the marking materlal of this invention;
Figure 2 is a sectional view of a marking material of thls lnventlon, which is given marking and applied to an adherend;
Figures 3 to 7 are sectional views illustrating conventlonal air-permeable marking materials wherein:
1 is the base;

2 is the adhesive layer;

3 is a hole;

4 is a porous layer;

5 is the adherend; and 6 is the marking.
Prior art air-permeable marking materials are explained by referring to Figures 3 to 7 wherein Figures 3 to 7 are sectional views illustrating conventional air-permeable marklng materials wherein 1 is the base; 2 is the adhesive layer; 3 is a hole; 4 is a porous layer; 5 is the adherend; and 6 is the lX82'~87 marking.
A marking material shown in Flgure 3 has a constructlon wherein an adhesive layer 2 is laminated to a base 1, and venting holes 3 are mechanically or chemically formed therein.
A marking ma~erial as shown in Figure 4 has a construction, wherein a base 1 is formed from an air-permeable fibrous material.
A marking material as shown in Figure 5 has a construction wherein an air-permeable porous layer 4 such as a foam, paper or fibrous material is formed between a base 1 and an adhesive layer 2. (See for example the laid-open publicat-ion of Japanese UM application Kokai (laid-Open) No. 90980/84).
A marking material as shown in Flgure 6 has a construction wherein an adhesive layer 2 is formed from an expanded porous material.
Furthermore, as shown in Figure 7, there is an air-lmpermeable marklng material having a construction wherein a base 1 is extremely thlck (about 250 ~m or A la .

.

' ' ' ` . ' , -2- 1~2~87 above) and the s-trength thereof is increased to enclose an escaping gas.
If a desired marking is provided on the marking material of Figure 3 and has too large a pore size (usually formed by printing methods such as offset, gravure or screen printing, or coating methods such as roll coating or knife coating), the surface conditions are bad with poor gloss, and the marking material cannot be put to vertical use. If the pore size is too small, pores are filled in forming the marking, and the air permeability is unfavorably inferior. The working of pore size is very difficult with bad workability.
In the marking material shown in Figure 4, the base l has low mechanical strength and is easily broken.
The smoothness of the base 1 is poor, and it is difficult to obtain a glossy marking material.
The marking material shown in Figure 5 has porous layer 4 of low mechanical strength which not only tends to cause layer cleavage but also is incapable of outgassing outside, thereby causing blistering, etc. on application to an adherend evolving a great volume of gases (for example application to molded RIM bumpers or FRP plates or application to polyethylene containers filled with gasoline).
The marking material shown in Figure 6 not only has a low bonding strength and tends to peel from the adherend but also is incapable of letting a large volume of gases escape to the outside, thereby causing blistering, etc. in the same manner as the marking material shown in Figure 5.
The marking material shown in Figure 7 arouses no problem in a short time after application to an adherend, but there is a problem of rather severe blistering, peeling, etc. with the lapse of time.

Summary of the Invention In accordance with the invention, there is provided a marking material comprising an adhesive layer , `
`
' ~82~87 60557-2989 on at least one surface of a base, said base being formed from a continuous porous plastic fllm having an average pore size of 0.2 to 50 ~m, an air permeability of 2 to 120 sec/100 cc and a thickness of at least 20 ~m.
Thus, the object of this invention is to provide marking materials to which a marking of good appearance conditions can be given without causing problems of peeling, blistering, etc. even on application to adherends evolving a great volume of gases.
Detailed Descri~tion Marking materials of this invention are explained by referring to Figure 1. Such materials have a construction wherein a base 1 ls formed from a contlnuous porous plastic film having an average pore slze of 0.2 to 50 ym, an air permeability of 2 to 120 sec/100 cc (measured by the Gurley method provided for in the JIS
P8117) and a thickness of at least 20 ~m, and an adhesive layer 2 contained on one slde of the base 1. A release material may be further laminated to the surface of the adhesive layer 2 to facilitate the handllng of the marklng materlals.
A

~4~ 1282~87 If the average pore size is smaller than 0.2 um, the holes are filled by the marking formed on the marking materials, and the air permeability is unfavor-ably inferior. If the average pore size exceeds 50 ~m, poor appearance of the marking is produced, and the materi~l cannot be placed into practical use. The average pore size within the range of 20 to 20 ,um is particularly preferred for providing glossy marking while obtaining effective air permeability.
If the air permeability (measured in sec/100 cc by the Gurley method provided for in the JIS P8117) exceeds 2 sec/100 cc (the lower value meaning a greater air permeability, and the value exceeding 2 sec/100 cc meaning a smaller value, the surface smoothness of the base 1 is inferior, and poor appearance of the marking is produced. If the air permeability is below 120 sec/100 cc (the numerical value is increased in this case), the air permeability is unfavorably inferior. The air perme-ability of 10 to 50 sec/100 cm is more preferred, considering the strength and air permeability performance of the base 1.
In the case of marking 6 provided on the whole surface of the marking materials as shown in Figure 2, a number of holes on the surface of the marking materials are filled by the marking 6 (ink or clear coating) to thus reduce the air permeability. However, an escaping gas A evolved from the adherend escapes even from the cut end surfaces of the marking materials. If the thickness of the base 1 is below 20 ~um, the area of th cut end surface of the marking materials is small, and the air permeability will be unfavorably inferior. The thickness of the base 1 is preferably in the range of 60 to 200 um taking into account the stabilized air permeability, economic efficiency and workability, etc. of the marking materials. The base 1 of this invention can be produced by the respective methods of sintering, mixed extracting, phase separation and drawing as disclosed in the - 5- ~282~87 post-exam publication of Japanese Patent Kokoku (Post-Exam Publn.) No. 5327/84 and the like, and general-purpose thermoplastic materials such as vinyl chloride, polyethylene, acrylic, urethane and polypropy-lene may be used.
An adhesive capable of providing sufficient adhesive force to the base to be laminated to the adherend may be sufficiently used, and a coating thickness within the ordinarily used range provides sufficient air permeability without performing working.
Therefore, a general-purpose adhesive such as acrylic, rubber, silicone and the like may be used.

Examples The marking materials of this invention are described in more detail by way of the following non-limiting examples.

Example 1 To a vinyl chloride organosol (manufactured by Sumitomo 3M Ltd.), was added 20% by weight of ethyl alcohol, and the resulting mixture was stirred with a propeller mixer at 800 rpm for 15 min. The stirred mixture was cast to form a continuous porous base by the phase separation method. An acrylic adhesive having a dry thickness of 30 um (manufactured by Sumitomo 3M Ltd.) and a release material were laminated to base 1 to form a marking material. The whole base surface of the resulting marking material was printed with a #3900 series ink manufactured by Sumitomo 3M Ltd. by screen printing.
After drying, the printing was similarly coated with "Clear Coating GA-l'~ manufactured by Sumitomo 3M Ltd. to a dry thickness of about 10 ~um. The resultant marking material was used to carry out the following tests:
(a) Blistering test ~ A 500-cc wide-mouthed polyethylene bottle manufactured by Sanko Plastic K.K. was filled with 1'~82~87 gasoline, and sealed, followed by application of the above~mentioned material to the surface of the bottle.
The marking material was allowed to stand at 25 C and 65%
RH for one month, and inspected visually for blistering.
~ The above-mentioned marking material was applied to an RIM molded article of an automobile bumper (manufactured by Mitsubishi Belting Ltd.) within 24 hours after molding. The resulting molded article was placed in an oven at 80C for 48 hours and then inspected visually for blistering.
Evaluation was made on the following criteria in both tests ~ and ~. -~ ....... No occurrence of blistering O ....... Occurrence of minute blistering A ....... Occurrence of partial blistering x ....... Occurrence of blistering on the whole surface (b) Appearance conditions The marking surface of the marking material similar to the above-mentioned (a) was inspected by visual examination, and evaluation was made on the following criteria:
..... Very glossy O ....... Glossy (Good appearance conditions) ~ ...... Matte x ....... Rough surface (Bad appearance, i.e., without gloss and bad conditions relative to the spread of ink) (c) Surface gloss Gloss of the marking surface of the marking material similar to the above-mentioned (a) was measured at 60 (a digital gloss meter "VG-2P-D3" manufactured by Nippon Denshoku Kogyo Co., Ltd. was used)~
Results of evaluation of the Example and the Comparative Example are shown in Tables 1 to 3.

~7~ ~ ~ 82 ~ 87 Table 1 shows evaluation results of tests with varying average pore size at a base thickness of 70 ~um and an air permeability of 30 sec/100 cc.
Table 2 shows evaluation results of tests with varying air permeability at a base thickness of 70 ~um and an average pore size of 10 lum.
Table 3 shows evaluation results of tests with varying base thickness at an average base pore size of 10 lum and an air permeability of 30 sec/100 cc.

Table 1 Average Blistering Appearance Surface pore size test conditions gloss (~m) ~ ~

0.2 O O O 90.0 Example 10 O ~ 85.5 ~ ~ ~\ 9 2 0.1 x x ~ 93.0 Comparative example ~ ~ x 4.5 Results x were obtained in both the blistering tests 1 and 2 of the conventional marking materials shown in Figures 3, 5, 6 and 7 cited above, and results x were obtained in the appearance conditions of the conventional marking material shown in Figure 4 cited above.

- 8- 128Z~87 Table 2 Ai r Per - Bl i ster ing Appearance Sur f ace b 1 ity te ,t conditions gloss lOOc ) (~) (~) 2 (~) ~ /\ 30.5 Example 30 ~ (~) O 85.5 120 ~\ ~ O 90 . 1 .

1 ~ ~ x 8.0 Comparative example 130 x x (~ 92 . 5 Table 3 Base Bl i stering AppearanceSurf ace thickness test conditions gloss ( ~Im ) ~

O O O 84.5 Example 55 O O O 88.0 ~ ~ O 88.5 , , 18 ~ ~ O 86.0 Comparatlve example x x O 89.0 Example 2 A continuous porous polypropylene film (manufactured by Sumitomo 3M Ltd. ) was used as a base, 9- ~282;~87 and the surface of the base was primed with a chlorlnated polypropylene (manufactured by Toyo Kasei Kogyo Co., Ltd.). An acrylic adhesive and a release material were laminated to the primed base similarly to Example l to form a marking material. Marking was provided on the base in the manner similar to Example l, and evaluation of the aforesaid blistering tests (respectively collected in one mark since similar results were obtained in ~ and ~), appearance conditions and surface gloss was made.
Evaluation results of this Example and a Comparative Example are shown in Tables 4 to 6.
Table 4 shows evaluation results of tests with varying average pore size at a base thickness of 80 ~um and an air permeability of 38 sec/lO0 cc.
Table 5 shows evaluation results of tests with varying air permeability at a base thickness of 80 ~m and an average pore size of 3.2 ~um. Table 6 shows evaluation results of tests with varying base thickness at an average base pore size of 3.2 um and an air permeability of 38 sec/lO0 cc.

Table 4 Average Blistering Appearance Surface pore test conditions gloss 0.2 O O 88.5 Example lO O O 82.0 50 ~ ~\ 11 . O

0.1 x ~ 91.5 Comparative _ example _ ~ x 5.0 - 1 0 ~ 87 Table 5 Air per- Blistering Appearance Surface e ~ ~ e ~ t~ u~ ~ i . on s glo s s 2 ~ _~ _ 16.2 Example 38 . 80.5 120 O ~ 90.5 .

1 x 5-.2 Comparative example 130 ~\ ~ _91.0 Table 6 Base Blistering Appearance Surface thickness test conditions gloss .
O O 84.5 Example 50 O O 84.8 ~ O 87.0 18 ~ O 86.2 Comparative example x O 87.5 As explained above, the base of the marking materials of this invention is formed from a continuous porous plastic film having an average pore size of 0.2 to .28~8~
50 ~m, an air permeability of 2-120 sec/100 Cc and a thickness of 20 ~m or above, and marking having good matte to glossy appearance conditions can be provided on the base. Furthermore, a marking material having sufficient air permeability can be obtained even if marking is provided all over the surface. Since there is no porous layer between the base and the adhesive layer, the marking materials having a high strength can be provided without causing layer cleavage.

Claims

1. Marking material comprising an adhesive layer on at least one surface of a base, said base being formed from a continuous porous plastic film having an average pore size of 0.2 to 50 µm, an air permeability of

2 to 120 sec/100 cc and a thickness of at least 20 µm.
is