JPS63105407A - Ultraviolet curable dielectric composition - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to novel ultraviolet curable dielectric compositions, particularly membrane touch switches.
itch).

BACKGROUND OF THE INVENTION Membrane touch switches are normally open, low-voltage, pressure-sensitive devices that have been used in a wide range of applications in recent years, including appliances, electronic games, keyboards, and other appliances.

This is typically a three-layer sandwich structure with conductive traces printed on the inside of the top and bottom layers, separated by a spacer sheet. Pressure applied to the top layer establishes instantaneous electrical contact between the top and bottom layers through the openings in the spacer sheet. Both flexible and rigid switches are possible. The former is typically printed on a flexible polyester base, while the latter uses a printed circuit board bottom plate.

Ease of design and manufacture allows the cost of touch switches to be lower than their electromechanical equivalents. Nevertheless, they still have to be manufactured from high-security electronic materials, and these materials have to be compatible with each other. Because the high cure temperatures of many inks available for cermet applications are not suitable for polymeric substrates, many polymeric thick film conductors and dielectrics have been developed for this application. Different chemistries are currently used for both types of inks, and different manufacturing options are also used.

In practice, many manufacturers first select a conductive ink and then look for a compatible dielectric. Selection is very critical in this application. This is because dielectrics are used both to insulate and enable conductors to cross and to encapsulate to prevent environmental damage. However, the lack of adequate adhesion of dielectrics to substrates and/or conductive inks has limited the market penetration of many dielectric compositions, particularly UV curable dielectric compositions.

Current manufacturing methods allow the dielectric to be screen printed;
It indicates that it is heat curable or ultraviolet curable. The faster cure obtained with the latter makes it a more cost-effective method, and the wide applicability of UV curing equipment makes it a practical tool. The dielectric must be compatible with the conductive ink and certain properties must be met. It must be a flexible, peel-resistant membrane, free of pinholes, and with good adhesion to the substrate and conductive ink. Cross applications also require that the conductive ink have good adhesion to the dielectric, often also specifying the adhesion of the dielectric to itself. Electrical requirements call for low dielectric constant, high insulation resistance, and high breakdown voltage. Physical and electrical properties must not deteriorate under various environmental conditions.

In an assembled switch, defects in the dielectric can result in electrical or physical destruction of the switch. Both material vendors and switch manufacturers rigorously test components under 1'resh and Hecelate aging conditions to reduce the probability of these occurrences. Electrical defects refer to shorts caused by pinholes, conductive impurities in the formulation, dielectric defects under stress or other pressurized environmental conditions. Physical defects arise from blistering, softening or cracking. Any of these can occur during the manufacturing process or during use. Blistering can occur due to incompatibility of the dielectric with the conductor or substrate and moisture sensitivity.

Softening can occur under high humidity conditions or with solvents from the conductive ink, and cracking can occur due to the inherent brittleness of the cured composition.

All of these problems can be prevented with properly formulated inks.

A more difficult problem is that of pedestal losses. Since this is closely related to the substrate, the problem is compounded by the large number of possible substrates. Polyester films are most commonly used in touch switches, although polycarbonate and polyimide films are occasionally used. Each film manufacturer typically offers different performance products with different surface properties due to variable processing methods and/or surface pre-treatments. The film may also be heat treated to reduce shrinkage during the subsequent curing process.

Different polyester films have different physical surfaces. For example, Mylar EL■500 and 500
Both polyester films of D'') show evidence of rough surfaces due to slip pre-treatment to facilitate handling of the films; whereas the polyester films of Mel 1nex■Q (6') have a very smooth surface. .My
lar■500D polyester film is 1, Myla
rOE L 500 polyester film has much smaller particles and gives a transparent appearance, but MyIar [
F] EL500 has a cloudy appearance. M el
1nex■0 polyester film is also very transparent, but it has the disadvantage that it is not easy to handle and tends to stick to itself.

As expected, adhesion to these surfaces is highly variable and not directly related to surface smoothness. Mel
fnex (81O) polyester films generally exhibit the lowest resistance.Physical surface properties are often overlooked, as membrane switch manufacturers often select substrates for reasons of cost, size stability, and appearance rather than microstructure. , can be critical to the performance of the ink from an adhesion standpoint.

SUMMARY OF THE INVENTION The present invention is therefore first directed to an improved screen printable dielectric composition having good adhesion to a wide range of substrates, the dielectric composition comprising: (a) 25- 35% by weight of an inorganic adhesive selected from talc, mica and mixtures thereof (adbcsio
(b) 75-65% by weight of an ultraviolet curable liquid composition dispersing finely divided particles of (n agent) and (b) 75-65% by weight of an acrylated polydiene oligomer; ) 35-75% by weight alkyl acrylate.

The present invention is directed to a membrane touch switch with upper and lower flexible layers.

In yet another aspect, the invention comprises upper and lower flexible layers having opposed conductive regions separated by an adhesive spacer layer and conductive traces extending therefrom and encapsulated within the layer of composition. It is aimed at membrane touch switches.

In yet another aspect, the present invention is directed to a membrane touch switch comprising upper and lower flexible layers, at least one of which has a plurality of intersecting electrically conductive regions separated from each other by layers of the composition. ing.

Adhesion Testing The most widely accepted standard for determining the adhesion of membrane switch materials is found in the literature (ASTM D3359-7 [!
.

This is the tape test described in Method B).

For films less than 5 mils thick, it is necessary to form a grid pattern on the substrate. The device for this purpose is Gar
dner/ Neotec Instrument D
visionof'pacif'ic 5cien
It can be obtained from tific. Sensation @X pressure tape (e.g. 3M 5cotch Bran
d 810 ) is applied onto the grating pattern and removed in continuous, sharp, pull-free movements. Depending on the degree of ink removal, adhesion is graded from OB to 5B.

The highest grade indicates no ink removal.

Many inks that fail this crosshatch test, however, exhibit acceptable adhesion in a simple tape pull test. This is due to adhesion loss due to detachment of the ink from the substrate due to excessive energy imparted to the ink during the cutting operation. If this energy is not stopped from moving laterally across the ink surface interface, these inks will give poor crosshatch adhesion.

It is often observed that inks with nominal crosshatch adhesion pass or fail depending on the type of cutting pattern. A few widely spaced cuts give less energy than several closely spaced cuts on the same unit area. The ASTM test described above is designed to increase the reproducibility of the crosshatch test by quantifying the applied transverse force at any particular condition.

In order to survive the pressure of prior art crosshatching, the polymer ink is made durable so that the applied force is absorbed or dissipated in the vicinity of the cut and is prevented from migrating to the ink surface interface. There must be. One way to do this is to increase the degree of cross-crosslinking. However, this technique is counterproductive in that the resulting composition is too brittle for touch switch inks.

Another method is to rubber-reinforce the composition with elastomeric inclusions. It is a widely used technique in epoxy chemistry. A third method is to use rigid packed particles such as alumina, silica, and glass spheres. Recently reported work combines these latter two methods in epoxy systems to yield hybrid-particle composites.

In these systems, dispersed rubbery particles increase the degree of localized plastic shear deformation around the debris, whereas rigid particles increase the extent of crack-plnni
ng) mechanism to increase cracking resistance.

The experimental rubber-reinforced UV curable dielectric composition has excellent crosshatch adhesion for the lumen, but not for smoother surfaces such as Mel 1 NexoO polyester film. This can be explained by the fact that in the former case the surface area to meet the dielectric is larger (and requires extra force for peeling). The composition has poor crosshatch adhesion to both rough and smooth polyester films, whereas dielectrics formulated as hybrid-particle composites are compatible with a wide variety of plastic films, including a gamut of various surface areas. It has been found to have excellent crosshatch adhesion to substrates of 20 to 30%. This improved adhesion is due to both the rubber reinforcement mechanism and the crack bonding of the filler.

Rigid-filled particles have been found to make a much smaller contribution to overall strength (and therefore adhesion). This is because similar compositions without elastomeric inclusions have much lower crosshatching.

DETAILED DESCRIPTION OF THE INVENTION The present invention is therefore directed to novel UV curable dielectric compositions containing both elastomeric and rigid fills that have excellent adhesion to a wide range of polyester surfaces.

Such elastomeric fillers can be added to the dielectric composition in a variety of ways. For example, micron-sized core-shell polymers such as U.S. Pat. No. 3,313.7
48 (Burk) can be mixed into the dielectric.

Another method is to incorporate an elastomeric polymer such as polyisoprene into the formulation. Although both of these techniques are effective to some extent, the most effective technique is to choose monomers and oligomers that contribute to both the elastomeric and non-elastomeric properties of the final composition.

According to the present invention, therefore, rubber fillers are incorporated into the composition in both ways, as acrylated rubber-modified epoxy resin oligomers and as acrylated polybutadiene oligomers. The rheology of the system is adjusted through the use of alkyl acrylates. - and difunctional acrylic acrylates are particularly preferred for this purpose. Interestingly, while the prior art has shown that a wide variety of filler materials work effectively, the composition of fillers that can be used in the present invention has been found to be quite critical. Ta. Only talc and mica were found to be effective for obtaining the high adhesion provided by the compositions of the present invention.

A. Inorganic Adhesives A wide range of inorganic fillers were tested for use as adhesives in the compositions of the present invention (see Examples 3-14). However, the only materials generally found to be effective are talc and mica.

The purity of talc and mica does not appear to be critical, and normal commercial qualities of these materials are satisfactory for use in the present invention. Single theoretical chemical composition (3M g 0.4Si
Unlike talc, which has 02 .H2O), mica occurs as a variety of different forms of aluminum silicates, of which muscovite and phlogopite have some commercial use. Any of these are suitable for use in the present invention. Mixtures of talc and mica can be used without disadvantage.

At least 25% by weight of talc and/or mica is required to obtain the desired level of adhesion of the compositions of the present invention. However, about 35% by weight of these adhesives is undesirable in that the cured composition becomes less flexible.

The talc and mica used according to the invention can be treated with a silane coupling agent to effect the adhesion of these fillers to the organic polymer component of the liquid curable component. This primarily improves the aging properties of the composition, especially under environmental pressure conditions.

A typical silane coupling agent has the structure R-3t-←OR')3. In the formula, R is an organic functional group that reacts with the organic polymer, and OR' is hydrolyzed and condensed with the 5t-OH group of the substrate to form 5t-0-3.
R −S i−←OH) giving an i-bond becomes 3,
It is a hydrolyzable group. Various silanes contain different types of organic functional groups. Possible silane coupling agents include amino functional silanes, methacrylate functional cationic silanes, polyamino functional silanes, mercapto functional silanes, vinyl functional silanes and chloroalkyl functional silanes.

B. Epoxy Resin Oligomer - The main component of the curable liquid component of the present invention, and the first rubber material, is an acrylated rubber modified epoxy resin oligomer. These materials can be made by reacting the epoxide portion of a polyoxide with the acid portion of a liquid carboxy-terminated homopolymer or copolymer of an unsaturated monocarboxylic acid and a conjugated diene. The manufacture of these materials is described in U.S. Pat. No. 3,892,819 (Najvar) and U.S. Pat.
No. 491 (Waters).

A preferred oligomer of this type is the reaction product of a bisphenol A-derived epoxy resin with acrylic acid and carboxyl-terminated butadiene/acrylonitrile copolymerization. The acrylated rubber modified epoxy resin oligomer accounts for 20-50% by weight of the curable liquid component, preferably 35-45% by weight.

C. Acrylated Polydiene Oligomer The second essential component of the curable liquid component, and the second rubbery material, is an acrylated polydiene oligomer. These materials are acrylates, usually diacrylates, of low molecular weight liquid conjugated diene oligomers of molecule Q2-4000.

A molecular weight of 0 oOm was particularly effective. The vinyl content of the oligomer is on the order of 115-30ffiJ1%;
A vinyl content of 20-2'5ffiR% is preferred. Acrylated oligomers of butadiene or isoprene can be used in the present invention.

The polydiene oligomer should be 5-25% by weight of the composition, preferably less than the amount of epoxy resin oligomer (used). 7-20% by weight acrylated polydienes, especially polybutadiene, are particularly preferred.

D. Alkyl acrylates Optionally, acryl acrylates make up a major portion of the curable liquid component of the present invention. In all cases, the alkyl acrylate must be liquid at room temperature. Mono- and multi-functional acrylates can be used in the present invention. However, the tri- or higher functional acrylate should represent no more than 10% by weight of the curable liquid component.

This is to prevent excessive crosslinking and shrinkage of the composition. Therefore - and difunctional liquids Very surprisingly, better pipeability was obtained using a mixture of -functional acrylates (30-60%) and difunctional acrylates (5-20%). More optimal properties were obtained when the -functional and difunctional acrylates accounted for 35-45% and 7.5-15% by weight of the curable liquid component, respectively.

Suitable alkyl acrylates include, but are not limited to, the acrylates and methacrylates described below.

Allyl acrylate tetrahydrofurfuryl acrylate triethylene glycol diacrylate ethylene glycol diacrylate polyethylene glycol diacrylate 1,3-butylene glycol diacrylate 1,4-butadienediol diacrylate diethylene glycol diacrylate 1,6-hexanediol diacrylate neopentyl glycol Diacrylate 2-(2-ethoxyethoxy)ethyl acrylate tetraethylene glycol Diacrylate pentaerythritol Tetraacrylate 2-phenoxyethyl Acrylate ethoxylation Bisphenol A Diacrylate trimethylolpropane Triacrylate glycidyl Acrylate isodecyl Acrylate dipentaerythritol Monohydroxy penta acrylate Pentaerythritol triacrylate 2- (N,
N-diethylamino)ethyl acrylatehydroxylower alkyl acrylates, such as hydroxyethyl acrylate, hydroxybrobyl acrylate, hydroxyhexyl acrylatebenzoyloxyalkyl acrylates, such as benzoyloxyethyl acrylate and benzoyloxyhexyl acrylatecyclohexyl acrylate n-hexyl acrylate dicyclopentenyl acrylate N-vinyl-2-pyrrolidone isobornyl acrylate isooctyl acrylate n-lauryl acrylate 2-butoxyethyl acrylate 2-ethylhexyl acrylate 2.2-methyl-(1,3-dioxolan-4-yl )
Methyl acrylate.

- In the case of functional acrylates, they are preferably of higher molecular weight and therefore of lower volatility. As can be seen from the above list, the alkyl portion of the acrylate is saturated with organic groups that are essentially inert, so long as the resulting acrylate is liquid at room temperature and can be mixed into the acrylated polydiene oligomer. A preferred alkyl acrylate combination is dicyclopentenyloxyethyl acrylate and tripropylene glycol diacrylate (see Examples 1 and 2).

E. Additives In addition to the main ingredients described above, the compositions of the present invention may contain various secondary materials to add or enhance their properties, such as:
Containing an elastomeric polymer, an initiator that makes the composition UV-curable, pigments (soluble or insoluble), and various printing aids such as leveling agents, antifoam agents, and thlckncr. You can also do it. These materials are known in the art and do not constitute a basis for non-obviousness of the present invention.

F. Formulation The compositions of the present invention are not difficult to formulate in that simple low energy mixing is sufficient to facilitate dissolution. Although it is necessary that the compositions form a stable mixture, it is not necessary that the compositions be completely mutually soluble. Indeed, immiscibility of these mixtures leading to microscopic phase separation and thus multiphase structures upon UV curing was expected.

G. Test Method The polyester film substrate used for the tube test is a commercially available 5 mil thick (127 μm) film. The various qualities evaluated are specified in the example. Polyimide substrates are also commercially available in 5 mil (127 .mu.m) thick films sold by DuPont under the trademark Kapton "". The polycarbonate film was a commercially available 5 mil, 127 μm thick (Genera J
It is a trademark of Electric Corporation (Lexan"').

Polymeric silver conductive ink is available from DuPont as Product 500.
It is commercially available as No. 7.

A 1 square inch print was made through a 280 mesh stainless steel screen resulting in a 1.1 mil (25.4 to 27.9 μm) thick test pattern. Adhesive testing for silver was done on 5007 silver conductor precured on MylaroEL 500 polyester film.

The 5007 was printed with a 280 mesh stainless steel screen and cured at 12oC for 1o. The silver print thickness was 0.5 to 0.7 mil (12.7 to 17.8 μm).

Reported rejuvenation test results are in accordance with ASTM D3359-7
Figure 8 shows a crosshatch graft run according to M cthod B of 8. There 11 in each direction
a grid pattern of cuts is formed in the dielectric to the substrate, pressure sensitive tape is applied and removed over the grid;
The adhesion properties were then compared according to the degree of removal using the following units.

5B The edges of the cut are completely smooth.

None of the squares in the grid are separated.

4B Small pieces of coating peel off at intersections.

Less than 5% of the area is affected.

3B Bits of coating flake off along edges and at intersections of cuts. The affected area is 5 on the grid.
1526.

2B The coating flakes along the edges and on the squares. The affected area is 15 to 35% of the grid.
It is.

1B The coating flakes as large ribbons along the edges of the cut. The entire square is peeling off. The area affected is 35 to 65% of the grid.

OB Frame formation and peeling are worse than 1.

All adhesion tests were performed on a 3/4 inch wide 3M5cotch.
A moderate blade (11 teeth spaced 1.5 mm apart) was used.

All dielectric prints are manufactured using equipment (RPC Industry).
s [stock] 8) Q CProcessor Modcll 202
AN, two 200 W/ 1inear jnch
40 ft/ under ultraviolet light (containing a 79 W/ linearcm) moderate pressure mercury vapor light bulb)
It was cured in minutes (20.3cm 7 seconds). The samples were cured in air approximately 3 inches from the lamp.

EXAMPLE Two initial compositions according to the invention were formulated using talc and mica as rigid-filling grafting agents, respectively. Twelve additional compositions were then produced. There, other known rigid fillers were used in place of mica and talc.

A list of the rigid fillers used in the 20 examples is shown in Table 1, and the extubation properties of each formulation are shown in Table 1I.

In Examples 15-20, several graft compositions were formulated to exhibit various criticalities with respect to liquid components.

Finally, in Example 21, a composition identical to Example 1 was formulated except that all rigid fillers were omitted.

Adhesion data for all 20 examples using a wide variety of substrates are shown in Table 1I.

1 Talc 2 Mica 3 Sodium-A-zeolite 4 Hydrated silicate clay 5 Titanium dioxide 6 Alumina 7 Calcium carbonate 8 3 Eiwa alumina 9 Trimethylolpropane triacrylate Microgel lO Silica, low crystal, natural microcrystalline "amorphous" 11 Silica, amorphous suphumed 12 Silica, low crystal, natural microcrystalline Novaculite 13 Silica, diatomaceous 14 Silica, silica gel 15-20 Talc 21 Control, without adhesive 22 Talc 23 Talc 24 Talc Example I UV-curable mixture , 26.09% by weight acrylated rubber modified epoxy resin, 7.34% by weight acrylated polybutadiene oligomer, 26.22% by weight
dicyclopentenyloxyethyl acrylate, 6
．． 52% by weight of tripropylene glycol diacrylate, 0.17% by weight of a predispersion of copper phthalocyanine dye in trimethylolpropane triacrylate (20:80), 2.44% by weight of 2-hydroxy-2-methyl- 1-phenyl-1-propanone, 0.
69% by weight of 2,2-jethoxyacetophenone, 0.
Made from 53% by weight silicone printing aid and 30.0% by weight talc. After printing and curing, this composition has a wide range of specifications as shown in Table 1I.
trum) gave excellent crosshatch adhesion on the W board.

Example 2 Example 1 was repeated except that mica was used instead of talc. After printing and curing, the second composition also showed excellent adhesion on a wide range of substrates, as shown in Table 1I.

Examples 3-14 Example 1 was repeated except that talc was replaced with another filler candidate as shown in Table 1I. These compositions did not exhibit the excellent adhesion on a wide range of substrates shown in Examples 1 and 2 using talc and mica.

Example 15 Example 1 was repeated except that the acrylated rubber modified epoxy resin was replaced with an acrylated epoxy resin.

This composition does not exhibit the excellent adhesion to a wide range of substrates exhibited by Example 1.

Example 16 Example 1 was repeated except that the acrylated rubber-modified epoxy resin was replaced with an acrylated Aroya group urethane resin. This composition does not exhibit the excellent adhesion to the wide range of substrates shown in Example 1.

Example 17 Example 1 was repeated except that the acrylated polybutadiene oligomer was replaced with an equivalent amount of tripropylene glycol diacrylate. This composition does not exhibit the excellent adhesion to the wide range of substrates shown in Example 1.

Example 18 Example 1 was repeated except that both the acrylated polybutadiene oligomer and dicyclopentenyloxyethyl acrylate were replaced with an equal amount of tripropylene glycol diacrylate. This composition does not exhibit the excellent adhesion to the wide range of substrates shown in Example 1.

Example 19 Example 1 was repeated except that dicyclopentenyloxyethyl acrylate was replaced with an equivalent amount of tripropylene glycol diacrylate. This composition does not exhibit the excellent adhesion to the wide range of substrates shown in Example 1.

Example 20 Example 1 was repeated except that both the acrylated polybutadiene oligomer and tripropylene glycol diacrylate were replaced with equal amounts of dicyclopentenyloxyethyl acrylate. This composition does not exhibit the excellent adhesion to the wide range of substrates shown in Example 1.

Example 21 Example 1 was repeated except that talc was omitted from the composition. This composition does not exhibit excellent adhesion to a wide range of substrates as did the corresponding talc-containing compositions of Examples 1 and 2.

Example 22 A UV curable mixture of 13.30 wt-% acrylated rubber modified epoxy resin, 13.2:3ffi
m% acrylated polybutadiene oligomer, 36.3
Predispersion of 3ffi weight % dicyclopentenyloxyethyl acrylate, 3.31 weight % tripropylene glycol diacrylate, 0.17 weight % copper phthalocyanine dye in trimethylolpropane triacrylate (20:80), 2 .44 weight percent 2-hydroxy-2-methyl-1-phenyl-1-propanone, 0.69 weight percent 2.2-jethoxyacetophenone, 0.53 weight percent silicone printing aid, and 30. Manufactured from 0wt96 talc. After printing and curing, this composition provided excellent crosshatch adhesion on a wide range of substrates, as shown in Table 1I.

Example 23 A UV-curable mixture was prepared by combining 38.94 wt.% acrylated rubber-modified epoxy resin, 3.31 wt.% acrylated polybutadiene oligomer, 1.4.23 L
[im% dicyclopentenyloxyethyl acrylate, 9.73% by weight tripropylene glycol diacrylate, 0.17% by weight copper phthalocyanine dye predispersion in trimethylolpropane triacrylate (20:80), 2 .44% by weight of 2-
hydroxy-2-methyl-1-phenyl-1-propanone, 0.69% by weight of 2.2-nidiethoxyaceIphenone, 0.53% by weight of silicone printing aid, and 3
Manufactured from 0.0% by weight talc. After printing and curing, this composition provided excellent crosshatch adhesion on a wide range of substrates, as shown in Table 11.

Example 24 A UV curable mixture was prepared by combining 38.94% by weight of acrylated rubber-modified epoxy resin, 3.31% by weight of acrylated polybutadiene oligomer, 10.72% by weight of dicyclopentenyloxyethyl acrylate,
13.23% by weight of tripropylene glycol diacrylate, 0.17% by weight of a predispersion of copper phthalocyanine dye in trimethylolpropane triacrylate (20:80), 2.44% by weight of 2-hydroxy-2- Methyl-1-phenyl-1-propanone,
0.69% by weight of 2,2-jethoxyacetophenone,
0.53ffi% silicone printing aid, and 30
．． Manufactured from 0% by weight talc. After printing and curing, this composition provided excellent crosshatch adhesion on a wide range of substrates, as shown in Table 1I.

Part ■-v Polyester of various compositions 2 5B 58 5B3
58 58 2B4 1
B IB IB5 0B
OB OB6 58
2B IB7 4B
IB IB8 2B O
B OB9 1B IB
0B to IB IB
lB11 1B IB
0B12 58 5B
lB13 1B IB
0B14 28 58
5B15 18 2B
lB16 3B 48 3B
17 5B 38 4B18
4B OB 0B19
2B OB 0B20 5
8 58 2B21 5B
IB 0B22 58
58 5B23 58 2
B IB24 5B I
B OB No. ■ Table (continued) Polyesters of various compositions 2 58 58 5B3
1B IB IB4 1
B IB IB5 0B
OB OB6 2B
IB OB7 2B I
B IB8 0B OB
OB9 0B OB
0B10 1 B I B
I B11 1B IB
0B12 1B IB 1B
13 0B OB 0B14
0B IB 0B15
2B IB 0B18 4
B IB 4B17 5B
OB 0B18 0B
OB 0B19 0B
OB lB2O4B OB
4B21 0B OB
0B22 58 58 5B
23 58 5B lB24
0B 2B OB No. ■ Table (continued) Polyesters of various compositions 1 58 58 5B2
58 58 5B3 18
2B 5B4 1B
IB IB5 0B
OB OB6 58 58
5B7 58 5B
5B8 2B IB
3B9 28 28 5B10
28 28 5B11 4
8 58 5B12 58
58 5B13 1B I
B 2B14 2B IB
2B15 4B IB
lB18 18 48
5B17 58 58 5B18
58 58 5B19 3
8 58 5B20 48
58 5B21 58 48
5B22 58 58
5B23 1B IB
5B24 58 58 5B The composition of Example 1, which is the best mode of the invention, has extremely excellent performance. They are shown in the following table.

. World 6 Trademark (1) Chemlink 5000 is a trademark of acrylated butadiene liquid oligomer (Sartomer).
Company.

Wc5t Chaster, PA).

(2) l1ycar @ is the carboxy-terminated liquid polymer quotient p (B, F, GoodrlcllChcmi
cals,] nc,, Akron.

O1+).

(3) K a p to mouth ■ is a trademark of polyimide film (E, 1.du Pont da N
Amours and Company.

Wilmi Bton, DE).

(4) Lexan■ is a trademark of polycarbonate film (General Electric CO., Ltd.)
5chcnectady.

NY).

(5) Lnminar @ is a polyester film commercial company (Toray Industries, Inc.
, Tokyo, Japan).

(6) M+inex■ is a trademark of polyester film (IcI Americas, Inc.).

(7) M y I a r■ is a trademark of polyester film (E, 1.du Pont de Nc
Mours and Company.

Wilmington, DIE).

(8) QC is the trademark for UV light curing equipment (R
PCl industries, Inc., Plainri
ld, IL).

(9) 5007 indicates polymeric silver conductive ink (E, 1.du PonL deNcmours an
dCompany.

Wilmigton, DE).

(10) 5cotc@ is a trademark of pressure-sensitive contact tape (
3M Corporation, Monguchi neapolis,
MN).

Claims (10)

[Claims] (1) (a) 25-35% by weight of finely divided particles of an inorganic adhesive selected from talc, mica and mixtures thereof, and (b) 75-65% by weight of a curable liquid dispersing the same. A composition comprising (i) 20-50% by weight acrylated rubber modified epoxy resin oligomer, (ii) 5-25% by weight acrylated polydiene oligomer, and (iii) 35-75% by weight alkyl acrylate,
a curable liquid composition comprising; a printable dielectric composition comprising; (2) (a) 25-35% by weight of finely divided particles of an inorganic adhesive selected from talc, mica and mixtures thereof; and (b) 75-65% by weight of a curable liquid dispersing the same. A composition comprising: (i) 20-50% by weight of an acrylated rubber-modified epoxy resin oligomer; (ii) 5-25% by weight of an acrylated polydiene oligomer; (iii) 30-60% by weight of an acrylated polydiene oligomer. a curable liquid composition comprising a functional alkyl acrylate; and (iv) 5-15% by weight of a difunctional alkyl acrylate. (3) The proportions of the components of the curable liquid composition are (i)
(ii) 7.5-15% by weight; (iii) 35-45% by weight; (iv) 7.5-15% by weight.
Compositions as described in Section. (4) A composition according to claim 1 containing up to 5% by weight of an inert dye. (5) The composition of claim 1 which is UV curable and contains 0.1-10% by weight of a photoinitiator. (6) The composition according to claim 1, wherein the inorganic particles are subjected to a silane coupling treatment. (7) The composition according to claim 1, containing 0.1-2.0% by weight of printing aid. (8) A membrane touch switch comprising upper and lower flexible layers having facing conductive regions separated by an adhesive spacer layer of the composition of claim 1. (9) having facing conductive regions separated by an adhesive spacer layer and having conductive traces extending therefrom and encapsulated within the layer of the composition of claim 1; Membrane touch switch with top and bottom flexible layer. (10) A membrane comprising upper and lower flexible dielectric polymer layers, at least one of which has a plurality of cross-conducting regions separated from each other of the composition of claim 1. touch switch.