Process for the manufacture of a glass container, glass container and related uses

Abstract

The present invention relates to a process for the manufacture of a glass container that comprises the steps of: a) providing a first glass element; b) providing a second element made of a material selected from: glass, ceramic, metal and metallic alloy; said first element and said second element, joined together, defining a containment cavity of said glass container; c) depositing a sealing composition comprising at least one glass frit dispersed in at least one dispersing liquid on at least one surface of at least one of said first element and said second element; d) positioning said first element and said second element in contact with each other so that said sealing composition is arranged between said first element and said second element; e) heating said sealing composition so as to melt said glass frit and form a sealing layer between said first element and said second element. The present invention further relates to a glass container, such as, for example, a bottle, a cup or a jar, and related uses.

Claims

1. A process for the manufacture of a glass container comprising the steps of: a) providing a first glass element; b) providing a second element made of a material selected from: glass, ceramic, metal and metallic alloy; said first element and said second element, joined together, defining a containment cavity of said glass container; c) depositing a sealing composition comprising at least one glass frit dispersed in at least one dispersing liquid on at least one surface of at least one of said first element and said second element, wherein said glass frit comprises, in percent by weight, based on the total weight of said glass frit: (i) 20%-40% SiO.sub.2; (ii) 30%-70% Bi.sub.2O.sub.3; (iii) 1%-7% alkaline metal oxides; (iv) 1%-25% of stabilizing oxides selected from the group consisting of transition metal oxides, Al.sub.2O.sub.3 and P.sub.2O.sub.5; d) positioning said first element and said second element in contact with each other so that said sealing composition is arranged between said first element and said second element; e) heating said sealing composition so as to melt said glass frit and form a sealing layer between said first element and said second element wherein said heating to melt said glass frit is carried out at a temperature in the range 500 C.-700 C.

2. The process according to claim 1, wherein said first element and said second element are made of glass.

3. The process according to claim 1, wherein: said first element is made of glass and formed by a forming method selected from: pressing, blow-blow and press-blow; said second element is made of glass and formed by a forming method selected from: pressing, blow-blow and press-blow, said second element being formed by a different method from the method used to form said first element.

4. The process according to claim 1, wherein said container is a bottle.

5. The process according to claim 4, wherein said first element is a glass element formed by blow-blow or press-blow and comprises one or more of the following components of said bottle: mouth, neck, shoulder and body.

6. The process according to claim 1, wherein said container is a bottle and said second element is made of glass and is the bottom of said bottle, said bottom being formed by pressing or press-blow.

7. The process according to claim 6, wherein said first element is a glass element formed by blow-blow or press-blow and comprises one or more of the following components of said bottle: mouth, neck, shoulder and body.

8. The process according to claim 1, wherein the thermal expansion coefficient of said glass frit is within the range 10-100.Math.10.sup.7 K.sup.1.

9. The process according to claim 1, wherein said glass frit comprises from 0.5% to 3% by weight of alkaline-earth metal oxides (percentages by weight referred to the total weight of the frit).

10. The process according to claim 1, wherein said glass frit has the following composition, in percent by weight, based on the total weight of said glass frit: (i) 20%-40% SiO.sub.2; (ii) 30%-70% Bi.sub.2O.sub.3; (iii) 1%-7% alkaline metal oxides; (iv) 1%-25% stabilizing oxides selected from the group consisting of ZnO, ZrO.sub.2, Al.sub.2O.sub.3 and P.sub.2O.sub.5.

11. The process according to claim 10, wherein said heating to melt said glass frit is carried out at a temperature in the range 550 C.-650 C.

12. The process according to claim 1, wherein said sealing composition deposited on at least said first element is heated to a temperature in the range 80 C.-350 C. to at least partially eliminate said dispersing liquid, before positioning said second element in contact with said first element.

Description

(1) The present invention will be described below with reference to the attached figures wherein:

(2) FIG. 1 is a schematic representation of a perspective view of a container according to the invention comprising two glass elements joined together;

(3) FIG. 2 is a schematic representation of a perspective view of the container of FIG. 1 performed along the section line II-II;

(4) FIG. 3 is a schematic representation of a section of the container of FIG. 1 performed along the section line II-II during the assembling step of the glass elements;

(5) FIG. 4 is a schematic representation of an enlarged view of a detail of FIG. 2.

(6) The container 1 according to the present invention is a glass container in the form of bottle, such as, for example, a bottle for packing a perfume.

(7) The container 1 comprises a first glass element 2 and a second glass element 3 which are joined by at least one sealing layer 4.

(8) According to the embodiment shown in the attached figures, the first glass element 2, obtained for example by means of the blow-and-blow forming technique, comprises a cylindrical hollow body 12, a shoulder 13 and a neck 14 having a mouth 15. The second glass element 3, obtained for example by means of the forming technique of pressing, comprises a circular bottom 11 which delimits, together with the first element 2, a containment cavity 16 accessible through the mouth 15.

(9) As visible in figures from 2 to 4, through the pressing technique, it is possible for example to confer to the bottom 11 of the second glass element 3 a personalized glass geometry, in which protrusions 11a and/or grooves 11b are provided which are positioned according to predetermined configurations.

(10) The sealing layer 4 is obtained by heating a sealing composition which comprises a glass frit dispersed in a dispersing liquid. In the case of the container shown in the attached figures, the sealing composition is applied along the surface perimeter of the bottom 11 in the form of a continuous thin layer. If desired, the sealing composition may also be applied along the lower edge of the hollow cylindrical body 12.

(11) According to a preferred embodiment, the sealing composition is preferably subjected to heating so as to eliminate the dispersing liquid and make the glass frit adhere to the surface of the round bottom 11.

(12) In the assembling step, the hollow cylindrical body 12 of the first glass element 2 is positioned in contact with the glass frit adhered to the bottom 11 of the second glass element 3.

(13) The glass frit is then subjected to heating at its melting temperature so as to soften it and make a structural welding between the first and the second glass element 2, 3. Upon cooling, the glass frit hardens forming the sealing layer 4 which joins the two glass elements 2, 3.

(14) The following examples are provided for purely illustrative purposes of the present invention and should not be considered as limiting the scope of protection defined by the enclosed claims.

EXAMPLE 1

(15) A sealing composition having the following composition was prepared: (weight percentages referred to the total weight of the sealing composition): glass frit 67% water 25% dipropylene glycol 5% surfactant 3%.

(16) The viscosity of the sealing composition at 25 C. is equal to 125 centistokes (ASTM D1200Ford cup 4measure: 34 seconds).

(17) The glass frit has the following composition (weight percentages referred to the frit weight): 32% SiO.sub.2; 53% Bi.sub.2O.sub.3; 5% alkaline and alkaline-earth metal oxides (2% Na.sub.2O, 1% CaO, 2% K.sub.2O); 10% stabilizing oxides (4% ZnO, 2% ZrO.sub.2, 2% TiO.sub.2, 1% Al.sub.2O.sub.3, 1% P.sub.2O.sub.5).

(18) The thermal expansion coefficient of the glass frit is equal to 85.Math.10.sup.7 K.sup.1 (ISO 7991:1987).

(19) The melting temperature of the glass frit is equal to 530 C.

(20) The sealing composition was used for manufacturing a glass container in the form of bottle.

(21) The container is composed of a first glass element (flat bottom of the bottle) formed by pressing and a second glass element (cylindrical body-shoulder-neck) formed by blow-and-blow. Both the elements are made from soda-lime glass. The containment cavity of the container has a capacity of 90 ml.

(22) The sealing composition was applied on the perimeter edge of the bottle bottom using a roll applicator. The second glass element was then positioned in contact with the sealing composition deposited on the first glass element.

(23) The assembled container was heated at 600 C. for 80 minutes and then cooled up to ambient temperature within 80 minutes obtaining a transparent sealing layer which joins the first and the second element.

(24) The container of the present invention was tested for assessing the mechanical and thermal resistance of the sealing layer, as well as the suitability of the container as a whole for staying in contact with food and in prolonged contact with potentially aggressive substances.

(25) For comparative purposes, two further containers of the same shape and capacity of the container according to the present invention were prepared by gluing the same glass elements with, respectively, a UV photo-curable polymeric glue (acrylic glue Loctite 350, Henkel) and a hot melt glue (polyurethane glue, Henkel 475a)

(26) Still for comparative purposes, a further mono-component container made of flint glass of the same external shape and capacity of the container according to the present invention was prepared through the blow-blow method.

(27) The comparative containers were subjected to the same tests for characterizing the container according to the invention. The results of the tests are shown in Tables 1 and 2.

(28) TABLE-US-00001 TABLE 1 TOTAL MIGRATION CHEMICAL DM 21 Mar. 1973 RESISTANCE THERMAL MECHANICAL (Test performed IMMERSION G1 RESISTANCE TO SHOCK STRENGTH in autoclave at (24 h, ambient DISHWASHER UNI EN 1183 CONTAINER ISO 2409 121 C., 1 bar) Temp.) EN 12875-2 (T = 50 C.) FLINT GLASS High Releases = Resistance to 1500 washing Breakings = CONTAINER Resistance; 3 mg/dm.sup.2 abrasion by cycles: Presence 0% (MONO- class: 0 nails: >100 of evident lines COMPONENT) repetitions that spoil the aesthetic of the product CONTAINER Insufficient Total No aesthetic 200 washing Breakings = SEALED Resistance; separation alteration. cycles: Total 0% WITH UV class: 3-4 of the two Resistance to separation GLUE components abrasion by of the two nails = 0 components repetitions CONTAINER Insufficient Total No aesthetic 200 washing Breakings = SEALED Resistance separation alteration. cycles: Total 0% WITH HOT Class: 3-4 of the two Resistance to separation MELT GLUE components abrasion by of the two nails = 0 components repetitions CONTAINER High No aesthetic No aesthetic 1500 WASHING Breakings = OF THE Resistance; alteration. alteration. CYCLES: Presence 0% PRESENT Class: 0 Releases = Resistance to of evident lines INVENTION 3 mg/dm.sup.2 abrasion by that spoil the nails >100 aesthetic of the repetitions product

(29) The results of the tests of Table 1 indicate that the container according to the present invention has the same characteristics of mechanical strength, chemical stability, resistance to chemical agents and thermal resistance of a mono-component container made of flint glass prepared by the blow-and-blow method.

(30) TABLE-US-00002 TABLE 2 HOT MELT CONTAINER UV GLUE GLUE OF THE TEST DESCRIPTION CONTAINER CONTAINER INVENTION 1 MANUAL Manual separation test C C C TRACTION of the assembled product 2 HANDLING OF Repeated actions of C C C THE SAMPLE insertion and extraction IN THE from the hive PACKAGING 3 ABRASION Abrasion by reciprocal C C C GLASS rubbing of bottles AGAINST GLASS 4 SIMULATION Repeated spraying (3-5 NC NC C USING WITH spray a day) of a G1 solution G1 for 10 days 5 THERMAL Hot-cold cycle (20 NC NC C CYCLE WITH C.-+40 C.) using G1 G1 as filling solution 6 PARTIAL 24 hours immersion in NC NC C IMMERSION solution G1 at ambient IN G1 temperature 7 PARTIAL 4 hours in immersion in NC NC C IMMERSION solution G1 at 55 C. IN HOT G1 8 THERMAL Hot-cold cycle (20 C C C SHOCK FOR C.-+40 C.) without DECORATED the product GLASS 9 THERMAL Hot (60 C.) immersion C C C SHOCK FOR and rapid transfer into GLASS cold water (20 C.) 10 THERMAL 24 hours ageing at 50 C. NC NC C CYCLE and subsequent manual traction 11 CONTACT Exposure to alcohol NC NC C WITH vapors for 24 hours at ALCOHOL 40 C. in a bell VAPORS 12 INTERNAL Immersion in solution G1 NC NC C DECORATION - at 40 C. for 10 days TEST AT 40 C. WITH G1 C = compliant (test passed) NC = non-compliant (test not passed)

(31) The tests of table 2 represent the tests of mechanical and chemical resistance which are typically carried out in the perfumery sector for assessing the suitability of a glass container for use in the packing of perfumes and cosmetic compositions in general.

(32) The test results of table 2 show that the container according to the present invention is suitable for the use in the packing of cosmetic compositions, as it complies with all the requirements.

(33) The results of the tests carried out on the comparative containers, instead, show that the glass containers assembled with UV and hot melt glues are not suitable for the use in the packing of cosmetic compositions, as they do not have the necessary characteristics of mechanical strength, chemical stability, mechanical and chemical resistance.