HEAT-SENSITIVE RECORDING MATERIAL

Abstract

A heat-sensitive recording material including a substrate, a heat-sensitive recording layer which includes N-(4-methylphenylsulfonyl)-/V-(3-(4-methylphenylsulfonyloxy)pheny-purea and/or N42-(3-phenylureido)phenyl]benzol sulfonamide, and an intermediate layer which is arranged between the substrate and the heat-sensitive recording layer and which includes calcined aluminum silicate, and a method for producing a heat-sensitive recording material and to the use of calcined aluminum silicate in an intermediate layer of a heat-sensitive recording material.

Claims

1.-28. (canceled)

29. A heat-sensitive recording material comprising: a substrate, which is a web-form substrate, having a front side and a reverse side opposite the front side; a heat-sensitive recording layer disposed to the front side of the web-form substrate, the heat-sensitive recording layer comprising: at least one dye precursor; and at least one color developer that is reactive with the at least one dye precursor and is a) a compound of a formula (I): ##STR00013## or b) a compound of formula (II): ##STR00014## or c) is a mixture comprising the compound of the formula (I) and the compound of the formula (II); an interlayer disposed between the substrate and the heat-sensitive recording layer and comprising calcined aluminum silicate; and a mass fraction of the calcined aluminum silicate in the interlayer being 50 to 90%, based on a total mass of a solids fractions in the interlayer.

30. The heat-sensitive recording material as claimed in claim 29, wherein the compound of the formula (I) is in a crystalline form in which an IR spectrum has an absorption band at 340120 cm.sup.1.

31. The heat-sensitive recording material as claimed in claim 29, wherein the calcined aluminum silicate in the interlayer is platelet-shaped.

32. The heat-sensitive recording material as claimed in claim 31, wherein the platelet-shaped, calcined aluminum silicate has an aspect ratio of at least one of: 3 to 100, 5 to 95, and 10 to 90.

33. The heat-sensitive recording material as claimed in claim 29, wherein a compound of the formula (II) is present as a color developer and the heat-sensitive recording layer or the heat-sensitive recording material comprises no compound of the formula (I).

34. The heat-sensitive recording material as claimed in claim 29, wherein a compound of the formula (I) is present as color developer and the heat-sensitive recording layer or the heat-sensitive recording material comprises no compound of the formula (II).

35. The heat-sensitive recording material as claimed in claim 29, wherein the heat-sensitive recording layer comprises a sensitizer.

36. The heat-sensitive recording material as claimed in claim 29, wherein the heat-sensitive recording layer comprises a sensitizer and the sensitizer is selected from the group consisting of 1,2-bis(3-methylphenoxy)ethane, 1,2-diphenoxyethane, 1,2-di(m-methylphenoxy)ethane, 2-(2H-benzotriazol-2-yl)-p-cresol, 2,2-bis(4-methoxyphenoxy)diethyl ether, 4,4-diallyloxydiphenyl sulfone, 4-acetylacetophenone, 4-benzylbiphenyl, acetoacidanilides, benzyl 2-naphthyl ether, benzyl naphthyl ether, benzyl 4-(benzyloxy)benzoate, benzyl paraben, bis(4-chlorobenzyl) oxalate ester, bis(4-methoxyphenyl) ether, dibenzyl oxalate, dibenzyl terephthalate, dimethyl terephthalate, dimethyl sulfone, diphenyl adipate, diphenyl sulfone, ethylenebisstearamide, fatty acid anilides, m-terpenyl, N-hydroxymethylstearamide, N-methylolstearamide, N-stearylurea, N-stearylstearamide, N-(2-hydroxyethyl)octadecanamide, N-(hydroxymethyl)octadecanamide, p-benzylbiphenyl, phenyl benzenesulfonate ester, salicylanilide, stearamide, ethylene glycol m-tolyl ether, and ,-diphenoxyxylene.

37. The heat-sensitive recording material as claimed in claim 29, wherein the heat-sensitive recording layer comprises a sensitizer and the sensitizer is 1,2-diphenoxyethane or benzyl naphthyl ether.

38. The heat-sensitive recording material as claimed in claim 29, wherein the heat-sensitive recording layer has a Bekk smoothness as determined to DIN 53107:2016-05 is at least one of: 100 to 1200 seconds and 150 to 1100 seconds.

39. The heat-sensitive recording material as claimed in claim 29, wherein a mass per unit area of the interlayer is in a range of at least one of: from 4.0 to 15.0 g/m.sup.2, from 6.0 to 12.0 g/m.sup.2, and from 7.0 to 10 g/m.sup.2, and a mass per unit area of the heat-sensitive recording layer is in a range of at least one of: from 1.5 to 6 g/m.sup.2, from 2.0 to 5.5 g/m.sup.2, and from 2.0 to 4.8 g/m.sup.2.

40. The heat-sensitive recording material as claimed in claim 29, wherein the mass fraction of the calcined aluminum silicate in the interlayer is at least one of 60 to 90% and 70 to 88%, based on the total mass of the solids fractions in the interlayer.

41. The heat-sensitive recording material as claimed in claim 29, wherein the mass fraction of the calcined aluminum silicate in the interlayer is 65 to 75%, based on the total mass of the solids fractions in the interlayer.

42. The heat-sensitive recording material as claimed in claim 29, wherein the interlayer further comprises: one or more constituents selected from the group consisting of biocides, binders, dispersants, release agents, defoamers, thickeners, and optical brighteners.

43. The heat-sensitive recording material as claimed in claim 29, wherein the interlayer comprises at least one dispersant.

44. The heat-sensitive recording material as claimed in claim 43, wherein the at least one dispersant is a sodium polyacrylate homopolymer.

45. The heat-sensitive recording material as claimed in claim 29, wherein the interlayer comprises at least one of a styrene-butadiene latex, starch, and methyl cellulose.

46. The heat-sensitive recording material as claimed in claim 29, wherein the substrate comprises one or more of paper, synthetic paper, cardboard, paperboard, and polymeric film.

47. The heat-sensitive recording material as claimed in claim 29, wherein the heat-sensitive recording layer further comprises one or more constituents selected from the group consisting of binders, sensitizers, pigments, dispersants, antioxidants, release agents, defoamers, light stabilizers, and optical brighteners.

48. The heat-sensitive recording material as claimed in claim 29, further comprising: a protective layer at least partially covering the heat-sensitive recording layer.

49. The heat-sensitive recording material as claimed in claim 29, further comprising: a layer of adhesive is disposed on the reverse side of the substrate, facing away from the front side of the substrate.

50. The heat-sensitive recording material as claimed in claim 29, further comprising: a release layer disposed on the heat-sensitive recording layer and is dehesive toward layers of adhesive.

51. The heat-sensitive recording material as claimed in claim 50, wherein the release layer comprises at least one compound containing organosiloxane groups or a wax.

52. The heat-sensitive recording material as claimed in claim 29, wherein the heat-sensitive recording material is configured as at least one of a product, an entry ticket, a flight ticket, a rail, a ship ticket, a bus ticket, a gaming coupon, a parking display ticket, a label, a till receipt, a bank statement, a self-adhesive label, a medical diagram paper, fax paper, securing paper, and a barcode label.

53. The heat-sensitive recording material as claimed in claim 29, configured in at least one of a barcode label, a self-adhesive ticket, a self-adhesive entry ticket, a self-adhesive proof of purchase, a self-adhesive label, a self-adhesive entry ticket, an entry ticket, a flight ticket, a rail ticket, a ship ticket, a bus ticket, a gaming coupon, a parking display ticket, a label, a till receipt, a bank statement, a medical diagram paper, fax paper, and security paper.

54. A method for producing a heat-sensitive recording material, comprising: providing or producing a substrate comprising a front side and a reverse side disposed opposite to the front side; providing or producing a first coating composition, the first coating composition comprising calcined aluminum silicate; applying the first coating composition to the front side of the substrate; drying and/or crosslinking the applied first coating composition, to form at least one interlayer; providing or producing a second coating composition, the second coating composition comprising at least one dye precursor and at least one color developer which is reactive with this dye precursor and which a) is a compound of a formula (I): ##STR00015## or b) is a compound of a formula (II): ##STR00016## or c) is a mixture comprising the compound of the formula (I) and the compound of the formula (II); applying the second coating composition to the at least one interlayer; and drying and/or crosslinking the applied second coating composition, to give a heat-sensitive recording layer.

55. The method for producing a heat-sensitive recording material, as claimed in claim 54, further comprising: providing or producing a release layer coating composition, the release layer coating composition comprising at least one compound containing at least one of organosiloxane groups or a wax; applying the release layer coating composition to the heat-sensitive recording layer or to a second interlayer; drying and/or crosslinking the applied release layer coating composition to form a release layer that is dehesive with respect to adhesives.

56. Calcined aluminum silicate in an interlayer of a heat-sensitive recording material, wherein the heat-sensitive recording material, besides the interlayer, comprises: a substrate, the substrate having a front side and a reverse side disposed opposite to the front side; and a heat-sensitive recording layer disposed to a front side of the substrate, the heat-sensitive recording layer comprising at least one dye precursor and at least one color developer which is reactive with the at least one dye precursor and which is a) a compound of a formula (I): ##STR00017## or b) a compound of a formula (II): ##STR00018## or c) is a mixture comprising the compound of the formula (I) and the compound of the formula (II); and wherein the interlayer is disposed between the substrate and the heat-sensitive recording layer, and wherein a mass fraction of the calcined aluminum silicate in the interlayer is 65 to 75%, based on a total mass of solids fractions in the interlayer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0224] FIG. 1 is a comparison of IR spectra in the wavenumber range from around 4000 to 2000 cm.sup.1 of the two crystalline forms of the compound of the formula (I);

[0225] FIG. 2 is a comparison of IR spectra in the wavenumber range from around 2400 to 400 cm.sup.1 of the two crystalline forms of the compound of the formula (I);

[0226] FIG. 3 is a comparison of IR spectra of the two crystalline forms of the compound of the formula (I);

[0227] FIG. 4 shows daylight resistance of the examples;

[0228] FIG. 5 is a graph of daylight resistance;

[0229] FIG. 6 shows temperature resistance of the examples;

[0230] FIG. 7 is a graph of temperature resistance; and

[0231] FIG. 8 is a graph of dynamic print density.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0232] The appended FIGS. 1, 2, and 3 are graphic reproductions (fine drawings) of machine-generated original spectra.

[0233] FIG. 1 shows a comparison of IR spectra in the wavenumber range from around 4000 to 2000 cm.sup.1 of the two crystalline forms of the compound of the formula (I). Depicted in the upper part and identified with a) is the IR spectrum of the crystalline form of the compound of the formula (I) used in the invention and having a melting point of 175 C. Depicted in the lower part and identified with b) is the IR spectrum of the crystalline form of the compound of the formula (I) used in the invention and having a melting point of around 158 C.

[0234] FIG. 2 shows a comparison of IR spectra in the wavenumber range from around 2400 to 400 cm.sup.1 of the two crystalline forms of the compound of the formula (I). Depicted in the upper part and identified with a) is the IR spectrum of the crystalline form of the compound of the formula (I) used in the invention and having a melting point of 175 C. Depicted in the lower part and identified with b) is the IR spectrum of the crystalline form of the compound of the formula (I) used in the invention and having a melting point of around 158 C.

[0235] FIG. 3 shows a comparison of IR spectra of the two crystalline forms of the compound of the formula (I). Depicted in the upper part and identified with a) is the IR spectrum of the crystalline form of the compound of the formula (I) used in the invention and having a melting point of 175 C. Depicted in the lower part and identified with b) is the IR spectrum of the crystalline form of the compound of the formula (I) used in the invention and having a melting point of around 158 C.

[0236] The inventive and comparative examples below provide further elucidation of the invention:

INVENTIVE EXAMPLE 1

[0237] The web-form substrate used is a base paper having a mass per unit area of 64 g/m.sup.2, produced on a Fourdrinier paper machine from bleached and ground hard wood and soft wood pulps, with addition, based on the total solids content (bone dry) of the pulp supplied to the paper machine, of AKD size with a mass fraction of 0.8%, as a stop sizing, and also with addition of other customary adjuvants.

[0238] In papermaking a distinction is made between three levels for the solids content of paper and pulp: bone dry (absolutely dry), air dry, and oven dry. This is reported in each case in % bone dry, % air dry, and % oven dry. Here, bone dry represents a paper or pulp with 0% water content. The basis used for the calculation for air dry is a standard moisture content (that which is basically necessary for the paper). In the case of chemical and mechanical pulp, the calculation mass is based in general on 90:100, i.e., 90 parts of pulp and 10 parts of water. The condition of paper or pulp after drying under specified, defined conditions is referred to as oven dry.

[0239] Applied to the front side is an interlayer with a mass per unit area of 9 g/m.sup.2, using a coating knife, the interlayer comprising the following composition in percentage mass fractions:

[0240] 83% of calcined aluminum silicate as pigment,

[0241] 12% of styrene-butadiene latex as binder,

[0242] 2.5% of starch as cobinder, and

[0243] 2.5% of further auxiliaries (biocide 0.05%, dispersant 0.35%, methylcellulose 0.2%, thickener 0.2%).

[0244] Applied to this interlayer comprising calcined aluminum silicate, by means of a roller knife coating device, is a heat-sensitive recording layer, with a mass per unit area of 3.2 g/m.sup.2. The aqueous coating material used for this purpose contains the following components, according to the formula reproduced in table 1:

TABLE-US-00001 TABLE 1 Amounts in mass fractions [%] (bone dry), based on the total mass of the heat-sensitive recording layer Dye 3-dibutylamino-6-methyl-7-anilinofluoran (ODB-2) 9 precursor Color N-(p-toluenesulfonyl)-N-3-(p- 20 developer toluenesulfonyloxyphenyl)urea (Pergafast 201 (BASF)) Sensitizer benzyl 2-naphthyl ether (BNE) 16 Binder polyvinyl alcohol-co-ethylene copolymer (EVOH) 15 Cobinder acrylate copolymer 10 methylcellulose 2 Pigment talc (platelet-shaped with an aspect ratio of 25) 16 88

[0245] Further constituents of the heat-sensitive recording layer, which are not stated in percentage terms and based on the total mass in mass fractions [%] (bone dry), include dispersants, defoamers, optical brighteners, thickeners, waxes, and crosslinkers.

[0246] Following the application of the heat-sensitive recording layer, it is dried and calendered, and here a value of 500 Bekk/sec according to DIN 53107:2016-05 (Title: Testing of Paper and BoardDetermination of the smoothness by the Bekk method) is measured for the front-side surface smoothness.

[0247] The web-form substrate produced, with interlayer and heat-sensitive recording layer, is coated on the front side (to the heat-sensitive recording layer) with a radically curing standard UV silicone system, using a patterned roll applicator. The solvent-free Evonik standard silicone system used for this purpose comprises a formulation which is reproduced in table 2. The silicone add-on here is around 1.2 g/m.sup.2.

TABLE-US-00002 TABLE 2 RC-711 silicone acrylate 25 mass fractions RC-902 silicone acrylate 50 mass fractions RC-1772 silicone acrylate (mixture with dulling agent) 25 mass fractions TEGO photoinitiator A-18 2 mass fractions

[0248] The furnish thus obtained, comprising release agent, is cured with a UV lamp (80 W/cm) under a protective gas atmosphere of nitrogen.

[0249] This gives a heat-sensitive recording material of one aspect of the invention wherein the release layer, comprising compounds containing organosiloxane groups, does not detach from the heat-sensitive recording layer. Even after storage for 30 days, the release layer comprising release agent cannot be detached from the heat-sensitive recording layer. The sensitivity of the recording material produced is good.

INVENTIVE EXAMPLE 2

[0250] Inventive example 1 was repeated, except that the compound used as color developer, rather than N-(p-toluenesulfonyl)-N-3-(p-toluenesulfonyloxyphenyl) urea (Pergafast 201 (BASF)) was the compound N-[2-(3-phenylureido)phenyl]benzenesulfonamide (NKK) having a melting point of 178 C.

INVENTIVE EXAMPLE 3

[0251] A layer of adhesive was produced on the reverse side of the substrate of the heat-sensitive recording layer produced in inventive example 1, by application of a polyacrylic resin adhesive.

[0252] The substrate was subsequently rolled up, causing the layer of adhesive to lie on the release layer comprising a compounds containing organosiloxane groups. Even after storage for 30 days, individual plies of the heat-sensitive recording material can be unrolled, without the release layer comprising release agent detaching from the heat-sensitive recording layer, or residues of the layer of adhesive remaining on the release layer comprising a release agent.

INVENTIVE EXAMPLE 4

[0253] A layer of adhesive was produced on the reverse side of the substrate of the heat-sensitive recording layer produced in inventive example 2, by application of a polyacrylic resin adhesive.

[0254] The web-form substrate was subsequently rolled up, causing the layer of adhesive to lie on the release layer comprising a compounds containing organosiloxane groups. Even after storage for 30 days, individual plies of the heat-sensitive recording material can be unrolled, without the release layer comprising release agent detaching from the heat-sensitive recording layer, or residues of the layer of adhesive remaining on the release layer comprising a release agent.

COMPARATIVE EXAMPLE 1

[0255] Inventive example 1 was repeated, but the pigment used in the interlayer comprised hollow-body pigments (particle size: 1.5 m) instead of the calcined aluminum silicate.

COMPARATIVE EXAMPLE 2

[0256] Inventive example 3 was repeated, but the pigment used in the interlayer comprised hollow-body pigments (particle size: 1.5 m) instead of the calcined aluminum silicate.

[0257] The daylight resistance was determined on the heat-sensitive recording materials from inventive examples 1 and 2 and also from comparative example 2. The heat-sensitive recording material from inventive example 1 shows an improvement in stability of around 3% (stability of the image and of the contrast) relative to the heat-sensitive recording material from comparative example 1, and the heat-sensitive recording material from inventive example 2 shows an improvement in stability of around 7% (stability of the image and of the contrast) relative to the heat-sensitive recording material from comparative example 1. The results are reproduced in FIGS. 4 and 5.

[0258] Determination of the Resistance of Heat-Sensitive Recording Materials in Daylight:

[0259] The daylight resistance was determined on the heat-sensitive recording materials from inventive examples 1 and 2 and also from comparative example 2.

[0260] For the metrological capture of the daylight resistance of a thermal printout on the heat-sensitive recording materials of inventive examples 1 and 2 and of comparative example 1, test thermal printouts of black/white checkered design were produced on each of the heat-sensitive recording materials under test, using an Atlantek Model 400 Thermal Response Test System from Global Media Instruments, LLC (USA), employing a thermal head with a resolution of 300 dpi and an energy per unit area of 16 mJ/mm.sup.2.

[0261] Following the production of the test thermal printout with black and white checkering, and after a rest time of more than 5 minutes, a determination of the print density was carried out at each of three locations on the black-colored areas and the uncolored areas of the test thermal printout, by a TECHKON SpectroDens Advancedspectral densitometer. The mean was formed in each case from the respective measurement values on the black-colored areas and the uncolored areas.

[0262] A test thermal printout was irradiated for 24 hours using a daylight lamp with an energy of 21 600 kJ/m.sup.2. After 24 hours, the thermal paper printout was removed and, again, a determination of the print density was carried out at each of three locations on the black-colored areas and the uncolored areas of the test thermal printout, by a TECHKON SpectroDens Advancedspectral densitometer. The mean was formed in each case from the respective measurement values on the black-colored areas and the uncolored areas.

[0263] The resistance of the printed image in % corresponds to the ratio between the mean formed of the print density of the colored areas before and after storage under the daylight lamp, multiplied by 100.

[0264] The heat-sensitive recording material from inventive example 1 shows an improvement in stability of around 3% (stability of the image and of the contrast) relative to the heat-sensitive recording material from comparative example 1, and the heat-sensitive recording material from inventive example 2 shows an improvement in stability of around 7% (stability of the image and of the contrast) relative to the heat-sensitive recording material from comparative example 1. The results are reproduced in FIGS. 4 and 5.

[0265] Determination of the Resistance of Heat-Sensitive Recording Materials (at 90 C. for One Hour):

[0266] For the metrological capture of the resistance of a thermal printout on the heat-sensitive recording materials of inventive examples 1 and 2 and of comparative example 1, test thermal printouts of black/white checkered design were produced on each of the heat-sensitive recording materials under test, using an Atlantek Model 400 Thermal Response Test System from Global Media Instruments, LLC (USA), employing a thermal head with a resolution of 300 dpi and an energy per unit area of 16 mJ/mm.sup.2.

[0267] Following the production of the test thermal printout with black and white checkering, and after a rest time of more than 5 minutes, a determination of the print density was carried out at each of three locations on the black-colored areas and the uncolored areas of the test thermal printout, by a TECHKON SpectroDens Advancedspectral densitometer. The mean was formed in each case from the respective measurement values on the black-colored areas and the uncolored areas.

[0268] A test thermal printout was suspended in a conditioning cabinet at 90 C. After one hour, the thermal paper printout was removed and cooled to room temperature and, again, a determination of the print density was carried out at each of three locations on the black-colored areas and the uncolored areas of the test thermal printout, by a TECHKON SpectroDens Advancedspectral densitometer. The mean was formed in each case from the respective measurement values on the black-colored areas and the uncolored areas.

[0269] The resistance of the printed image in % corresponds to the ratio between the mean formed of the print density of the colored areas before and after storage in the conditioning cabinet, multiplied by 100.

[0270] The heat-sensitive recording material from inventive example 1 shows an improvement in the image stability of around 1% relative to the heat-sensitive recording material from comparative example 1, and the heat-sensitive recording material from inventive example 2 shows an improvement in background stability of around 7% (stability of the contrast) relative to the heat-sensitive recording material from comparative example 1. The results are reproduced in FIGS. 6 and 7.

[0271] In comparison with the heat-sensitive recording materials from inventive example 1 and comparative example 1, shown in FIG. 9, the recording material from inventive example 2 shows no background graying at all. The background image remains absolutely white.

[0272] Determination of the Dynamic Print Density:

[0273] For the metrological capture of the dynamic print density of a thermal printout on the heat-sensitive recording materials of inventive examples 1 and 2 and of comparative example 1, ten rectangles each with different energy inputs were printed on each of the heat-sensitive recording materials under test. The test thermal printouts were made using an Atlantek Model 400 Thermal Response Test System from Global Media Instruments, LLC (USA). Employed in this case was a thermal head with a resolution of 300 dpi, and an energy per unit area of 3.22, 4.62, 6.07, 7.49, 8.88, 10.32, 11.74, 13.17, 14.57, and 16.00 mJ/mm.sup.2.

[0274] Following the production of the test thermal printout, and after a rest time of more than 5 minutes, a determination of the print density was carried out at each of three locations on each of the black-colored areas of the test thermal printout, by a TECHKON SpectroDens Advancedspectral densitometer. The mean was formed in each case from the respective measurement values on the black-colored areas.

[0275] The dynamic print density was determined on the heat-sensitive recording materials from inventive examples 1 and 2 and also from comparative example 2. At higher energies (from around 7 mJ/mm.sup.2), the heat-sensitive recording materials from inventive examples 1 and 2 display a higher print density (sensitivity) than the material from comparative example 2. Moreover, the materials display a higher maximum print density (Dmax) and a higher print density at higher energies (16 mJ/mm.sup.2). The results are reproduced in table 3 below and in FIG. 8.

TABLE-US-00003 TABLE 3 3.22 4.62 6.07 7.49 8.88 10.32 11.74 13.17 14.57 16.00 (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) (mJ/mm.sup.2) Inventive 0.06 0.19 0.70 1.14 1.39 1.47 1.50 1.44 1.38 1.31 example 1 Inventive 0.06 0.16 0.64 1.09 1.38 1.46 1.45 1.44 1.41 1.38 example 2 Comparative 0.07 0.19 0.66 1.06 1.32 1.42 1.44 1.40 1.35 1.28 example 1

[0276] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.