Abstract:
A photocurable composition is provided which includes al having bottom and side walls which define a chamber a photocurable material disposed in-the chamber. The wall circulmacribe the bottom wall and includes a rant so that the side wall will substantially attenuate nic radiation while minimally attenuating visible light ng an approximating spectral wavelength greater than nanometers. By that arrangement, the level of the ocurable material may be visualized through the side while still providing sufficient attenuation of nic radiation to provide for long term storage of the ocurable material without substantial curing thereof.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This Patent Application is a continuation of application Ser. No. 09/122,677 filed Jul. 27, 1998, now U.S. Pat. No. 5,996,796 which is a continuation-in-part Application of an application entitled PACKAGED PHOTOCURABLE COMPOSITION, Ser. No. 08/743,646, filed Nov. 4, 1996, now U.S. Pat. No. 5,785,178. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field Of The Invention 
     This invention relates to a packaged photocurable composition that includes a squeezable vial having a chamber that receives a quantity of photocurable material. 
     2. Description of the Related Art 
     Many liquid and semi-liquid compositions used in small quantities in the household, commercial or industrial applications are sold in small vials, such as dropper bottles, squeezable applicators and the like. Typically, such vials are relatively inexpensive and are disposed of once their contents have been exhausted or have not been used by a specified expiration date. 
     Many small vials used for containing and dispensing liquid and semi-liquid compositions are made of a flexible polymeric material. To dispense the composition, opposed wall portions of the vial are squeezed together by finger pressure to expel the composition through an outlet. The flexible wall portions are an advantage in that the user can control, to some degree, the amount and flow rate of the composition that is dispensed. In addition, flexible wall portions are less likely to break if the vial is unintentionally dropped or subjected to other kinds of abuse in comparison to vials made of glass or other rigid materials. 
     Squeezable polymeric vials have been long used for various medical and dental preparations. Examples include vials for eye and ear medications, suntan and sun screen compositions, body lotions, cosmetics, topical ointments and insect repellents. Commercial and industrial applications include compositions for film developing and other photographic applications, adhesives (such as cyanoacrylates), lubricants and the like. 
     Many squeezable vials are made of polymeric material that is sufficiently transparent or translucent so that the user may visually estimate the amount of a composition remaining in the vial. In some instances, the transparent or translucent material helps the user ascertain whether or not the composition has degraded. For example, the user may be able to determine whether or not an adhesive has unduly hardened or thickened by shaking the vial and observing the fluidity of the contents through the polymeric wall portions. 
     Some compositions that are contained in squeezable vials are curable upon exposure to light having wavelengths in the visible spectrum. Examples of photocurable compositions include certain dental (including orthodontic) adhesives and primers, dental luting cements and other dental preparations such as sealants and crown build-up material. In the past, vials containing such photocurable compositions have included a sufficient amount of pigment, such as carbon black, that absorbs light and blocks substantially all of the light from entering the chamber in the vial that would otherwise unduly cure the contained composition. 
     Unfortunately, opaque squeezable containers are not entirely satisfactory, since the user cannot visibly ascertain,the amount of composition remaining in the vial or whether it has degraded. Some vials, and especially vials containing dental compositions, are relatively small and contain only a small amount of photocurable composition. With such vials, it is difficult to determine the amount of photocurable composition remaining therein by lifting the vial and estimating its weight, since the ratio of the weight of the vial to the weight of the composition is relatively large. 
     SUMMURY OF THE INVENTION 
     The disadvantages noted above with respect to conventional squeezable vials have been overcome by the present invention. In one aspect, the invention concerns a packaged composition that includes a vial formed by a bottom wall and an elastic side wall circumscribing the bottom wall to define a chamber. The side wall has an upper section shaped to form an outlet in open communication with the chamber. The bottom and side walls are formed of a polymeric material having a colorant added thereto for substantially attenuating actinic radiation and at least upright portion of the side wall is capable of transmitting light having wavelengths greater than 500 nanometers substantially uniform wall thickness. The packaged composition further includes a photocurable material disposed in the chamber that is cured responsive to exposure of actinic radiation. The photocurable material is dispensed through the outlet responsive to portions of the side wall being displaced from an initial position to a position closer together. The displaced portions of the side wall subsequently substantially return to the initial position. 
     Looking at the invention from another aspect, such concerns a packaged composition including a vial formed by a bottom wall and an elastic side wall circumscribing the bottom wall to define a chamber. The side wall has an upper section shaped to form an outlet in open communication with the chamber. The bottom and side walls are formed of a polymeric material having a colorant added thereto for substantially attenuating actinic radiation while minimally attenuating visible light having an approximating spectral wavelength greater than 500 nanometers through the side wall. The colorant has a color in the orange portion of the visible light spectrum. The side wall has a substantially uniform wall thickness. The packaged composition further includes a photocurable material disposed in the chamber and is cured responsive to exposure of actinic radiation. The photocurable material is dispensed through the outlet responsive to portions of the side wall being displaced from an initial position to a position closer together. Subsequently, the displaced portion of the side walls substantially return to their initial position. The packaged composition also includes a label secured to an external surface of a first portion of the side wall and extends from a position adjacent the bottom wall to a position adjacent the upper section thereof for enhancing visibility of a level of the photocurable material through a second portion of the side wall. 
     From still another aspect, the present invention concerns a packaged composition that includes a vial formed by a bottom wall and an elastic side wall circumscribing the bottom wall to define a chamber. The side wall has an upper portion shaped to form an outlet in open communication with the chamber. The bottom and side walls are formed of a polymeric material having a colorant added thereto for substantially attenuating actinic radiation, while minimally attenuating visible light having an approximating spectral wavelength greater than 500 nanometers through the side wall. The side wall has a substantially uniform wall thickness in an approximating range of 0.015-0.025 inches. The packaged composition further includes a photocurable material disposed in the chamber and being cured responsive to exposure of actinic radiation. The photocurable material is dispensed through the outlet responsive to portions of the side wall being displaced from an initial. position to a position closer together. Subsequently the displaced portions of the side wall substantially return to their initial position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a packaged composition in accordance with one embodiment of the invention, and wherein a vial is cut-away in partial section in order to illustrate a quantity of the photocurable composition contained therein; 
     FIG. 1A is an enlarged sectional view of an upper portion of a vial side wall of the present invention; 
     FIG. 2 is a side elevation view of a packaged composition according to another embodiment of the invention; 
     FIG. 3 is a horizontal sectional view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a side elevation view somewhat similar to FIG. 1 but in accordance with yet another embodiment of the invention; 
     FIG. 5 is a horizontal sectional view taken along line  5 — 5  of FIG. 4; and, 
     FIG. 6 is a view somewhat similar to FIG. 5 except in accordance with still another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A packaged photocurable composition according to one embodiment of the invention is illustrated in FIG.  1  and is designated by the numeral  10 . The packaged photocurable composition  10  broadly includes a vial  12  and a photocurable material  14  therein. 
     The vial  12  includes a bottom wall  20  from which extends an elastic side wall  16  circumscribing the bottom wall to define a generally cylindrical internal chamber  18  therein. The photocurable material  14  is received within the internal chamber  18 . 
     The side wall  16  has an upper section  17  shaped to form a neck portion  22  that terminates in an outlet  26 . The neck portion  22  is provided with a threaded section  24  for coupling to a conventional threaded closure cap. The closure cap (not shown) has a dispensing opening and a closure for selectively covering that opening. A similar closure cap is described in U.S. Pat. No. 5,328,058, and such could be applied to the vial  12 . Other types of dispensing outlets and closure caps may also be utilized. 
     The vial  12 , including the elastic side wall  16  with its upper section  17 , and the bottom wall  20  are preferably integrally molded and made of a polymeric material. The photocurable material  14  is dispensed from the vial  12  by displacing portions of the side wall  16  from an initial position, such as where opposing sides of the vial are substantially parallel, to a position where the sides are displaced so as to be closer together. The sides of the vial  12  are sufficiently elastic to substantially return to their initial position once the finger pressure of a user is released. Thus, in order for the vial  12  to be squeezable, the polymeric material from which it is formed should havp a flexural modulus that is preferably less than 200,000 kg/cm 2 , and more preferably less than approximately 20,000 kg/cm 2 , and most preferably less than 2,000 kg/cm 2 . Referring additionally to FIG. 1A, the side wall  16  has a thickness D that is preferably in the range of approximately 0.005-0.1 inches (0.12-2.5 mm), and more preferably in the approximating range of 0.01-0.06 inches (0.25-1.5 mm). Most preferably, side wall  16  should have a thickness dimension D in the approximating. range of  0 . 010 . 03  inches (0.25-0.75 mm). 
     As will be discussed in following paragraphs, it is important that the wall thickness be substantially uniform throughout the side wall  16 . Therefore, as the side wall transitions to the upper section  17 , both the wall thickness C of the radiused portion  15  and the thickness B and A of the upper wall section  17  that transitions inwardly to form the outlet  26  should all be substantially equal to the thickness D. Thus, for a vial having a nominal thickness of 0.020 inches for the dimension D, the dimensions A, B and C should not vary more than ±0.005 inches in order to maintain a proper level of electromagnetic radiation absorption and transmissivity. 
     The flexural modulus and the thickness of the elastic side wall portions  16  are selected to enable opposed sections of the wall portion  16  to be readily squeezed together by finger pressure. As the opposed sections are squeezed together, free space in the chamber  18  is reduced and the photocurable material  14  in the chamber  18  is expelled through the outlet  26 . The polymeric material from which the vial  12  is formed is sufficiently elastic to enable the squeezed sections thereof to fully self-recover from the deformed state to the original state of the vial, once the finger pressure is released, thereby re-assuming the normal, generally cylindrical configuration thereof. 
     As will be discussed in following paragraphs, another attribute of the polymeric material utilized for vial  12  is its transmissivity of visible light, allowing a user to ascertain the level of the photocurable material  14  disposed in chamber  18 . Suitable polymeric materials for making the vial  12  include blow molded low density polyethylenes (“LDPE”) such as No. 5104 from CHEVRON, high density polyethylene (“HDPE”), polyvinyl chloride (“PVC”), poly(ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate) (“PETG”), or poly(ethylene terephthalate) (“PET”). The selected polymeric material must also be compatible with the photocurable material  14  and not unduly degrade over an extended period of time. 
     The photocurable material  14  is a liquid or semi-liquid material that is curable upon exposure to selective actinic radiation, i.e., wavelengths of light (electromagnetic radiation) that effects curing in the material. Examples of photocurable material include dental (including orthodontic) adhesives and primers, luting cements, crown build-up material and sealants. Such materials have a photoinitiator (such as camphor quinone (“CPQ”) ) that initiates curing when exposed to actinic radiation, which may be a portion of the electromagnetic spectrum having a wavelength less than 500 nm. The photocurable material  14  may also be a non-dental material such as a medical preparation or a composition intended for household, commercial or industrial application. The viscosity of the photocurable material must be within a range of values to be easily dispersed by squeezing portions of the side wall  16 , and flow to the bottom of the chamber  18  without substantially coating the internal surface of the side wall, and thereby inhibiting visualization of the remaining portion of the photocurable material in the vial  12 . Photocurable material  14  should have an absolute viscosity less than or equal to approximately  100  centipoise. With respect to kinematic viscosity, photocurable materials having viscosities within the approximating range of 120-1200 centistokes have been successfully utilized in the instant invention. 
     The vial  12  and in particular, the side wall  16  preferably transmits less than approximately 1.0% of actinic radiation, and more particularly, transmits less than approximately 0.5% of actinic radiation. Most preferably, less than approximately 0.2% of actinic radiation is transmitted through the side wall  16 . As a result, the photocurable material  14  is able to remain in the chamber  18  for an extended period of time without unduly curing therein. 
     However, at least one upright portion of the side wall  16  must be capable of transmitting light having wavelengths greater than 500 nm, in order to transmit sufficient light in the visible spectrum to allow a user to see the photocurable material  14  therethrough, which photocurable material may be a transparent liquid. In that way, the level of the material  14  in chamber  18  can be determined. 
     As an example, if the photocurable material  14  is a dental adhesive that includes the photoinitiator that comprises CPQ, the adhesive will begin to cure when exposed to light having wavelengths approximating 470 n. Preferably, the wall material of the vial containing the dental adhesive blocks the passage of most of the light having such a wavelength, as well as light having wavelengths relatively close thereto. In such example, the wall portions preferably transmit less than approximately 1.0% of light having wavelengths in the range of 400 nm to about 500 nm. 
     In order to achieve the necessary wavelength sensitive transmittance, colorants such as pigments and/or dyes are useful for making the polymeric material absorb selective wavelengths of impinging electromagnetic radiation. The amount of colorant necessary per unit of polymeric material to provide the desired protection will vary depending on a number of factors, such as the particular colorant selected, the thickness of the wall sections of the vial, the uniformity of the wall sections of the vial, the wavelength of light to be absorbed and the capacity of the non-colorant treated polymeric material to absorb the light in the wavelengths to be filtered. 
     A suitable colorant for the dental adhesive vial mentioned above is a colorant having a manufacturer&#39;s identification No. 70344 HCP from TEKNOR COLOR COMPANY. The colorant is in the orange portion of the visible light portion of the electromagnetic spectrum. While colorants in the red portion of the spectrum have been found to suitably block actinic radiation, such as wavelengths less than 500 nm, they do not transmit sufficient visible light having wavelengths greater than 500 nm to allow a user to easily visualize the level of the photocurable material  14  within the vial  12 . On the other hand, colorants within the yellow portion of the visible light spectrum transmit sufficient light having wavelengths greater than 500 nm, but do not sufficiently attenuate wavelengths less than 500 nm. It is a necessary requirement to substantially attenuate actinic radiation while minimally attenuating visible light having an approximating spectral wavelength greater than 500 nm, and colorants in the orange wavelengths have been found to meet that criteria. 
     The vial  12  may be made, for example, by mixing 6% by weight of the colorant with 94% of the LDPE “carrier” resin. The resultant mixture is then mixed with LDPE (such as No. 5104, from CHEVRON) at a “let-down” ratio of 5:1 (i.e., a ratio of five parts LDPE to one part carrier and colorant mixture by volume). More accurately, the overall mixture of colorant and resin should have a colorant concentration of approximately 1%. Preferably, the carrier resin has a slightly lower melting temperature than the melting temperature of the remaining quantity of LDPE, to facilitate mixing. A suitable carrier resin is yukalon Lm-30 from MITSUBISHI PETRO. 
     The amount of electromagnetic radiation attenuation is also dependent upon the thickness of the material through which the radiation passes. For vial  12 , the side wall  16  has a thickness through which the electromagnetic radiation passes. The thicker the side wall  16  is, the greater the attenuation effect. However, as the vial  12  is intended to be a “squeeze bottle” the wall thickness cannot be so thick as to impede the displacement of opposing sides of the vial using only finger pressure. Thus, once a vial polymeric material and thickness has been selected, it then becomes critical that the wall thickness remain substantially uniform throughout the contours of the vial. As the upper section  17  of the side wall  16  is contoured to form the neck  22  of the vial and terminate in the outlet  26 , there are several radiused bends in the cross-sectional contour of the vial. It is important that these radiused regions have substantially the same thickness as the unradiused portions thereof, in order not to attenuate less actinic radiation therethrough, or attenuate too much light in the wavelengths greater than 500 nm. Thus, the thickness of the vial radiuses A and C should be substantially equal to the wall thickness B and D. Similarly, the thickness of the side wall  16  where it interfaces with the bottom wall  20  should have a thickness which is not less than the minimum end of the side wall thickness tolerance. 
     A packaged composition  10   a  according to another embodiment of the invention is illustrated in FIGS.  2  and  3 . The packaged composition  10   a  includes a vial  12   a  and a photocurable material  14   a  therein. Preferably, the vial  12   a  and the photocurable material  14   a  are the same or similar to the vial  12  and photocurable material  14  previously discussed, except for the differences noted in the paragraphs that follow. As a consequence, a detailed description of such previously discussed items will not be repeated. 
     As shown in FIGS. 2 and 3, the elastic side wall  16   a  of the vial  12   a  includes a label  30   a  that extends around the circumference of the vial  12   a , and extends longitudinally along the length of the vial from a portion adjacent the bottom  20   a  to a position substantially adjacent the beginning of the upper section  17   a  of side wall  16   a . The label  30   a  includes a first section  32   a  that is opaque or substantially opaque to the passage of light, especially light having wavelengths in the visible spectrum. The label  30   a  may also include a second section  34   a  that is transparent or translucent to light having wavelengths in the visible spectrum. Both of the sections  32   a  and  34   a  may be formulated to block the passage of all or at least a substantial portion of actinic radiation. 
     The label  30   a  may be made of any of a number of suitable materials, including polymeric film stock. Examples of suitable material include polyethylene labels from FLEXCON COMPANY, INC. Optionally, the label  30   a  can be made of a co-extruded polyethylene film wherein the first section  32   a  is made of an extruded mixture of polyethylene and black, white or other pigment, while the second section  34   a  is simultaneously extruded from a stream of polyethylene without such pigment. As another alternative, the label  34   a  may be made of transparent or translucent polyethylene film and a quantity of ink applied to the first section  34   a  to render it opaque to the passage of light in the visible light spectrum. As a further option, the second section  34   a  is eliminated to define a gap between opposing edges of the label  30   a , with the photocurable material  14   a  being viewed through the gap between opposing end portions of the label  30   a . The window created between the opposing edges of the label  30   a , or through the unpigmented section  34   a  of label  30   a  enhances the contrast between the photocurable material and the air space above the photocurable material in the internal chamber  18 . As many of the photocurable materials which may be packaged in vial  12  are substantially transparent, it is important that a contrasting background be created for viewing the height of the photocurable material within the vial  12 . For vials  12   a  of small size, it is currently not technically feasible to co-mold the vial itself with a single portion thereof having a substantially transparent or translucent portion and a remaining portion being substantially opaque to visible light. Therefore, for such vials of small size, it is critically important that the label produce a substantially opaque section which occupies more than  50 % of the circumference of the vial for providing contrast to view the photocurable material through a remaining portion of the circumference of the vial, i.e. the portion  34   a.    
     Although not shown in the drawings, one side of the label  30   a  is coated with a pressure-sensitive adhesive to firmly secure the label  30   a  to the upright side wall  16   a . An example of a suitable adhesive is a 0.0008 inch (0.04 mm) thick layer of a permanent acrylic adhesive (No. V-157 from FLEXCON). Preferably, where the label  30   a  includes a transparent portion  34   a , adjacent end sections of the label  30   a  overlap in order to reduce the likelihood of flagging and assure that the end portions of the label  30   a  tightly adhere to the side wall  16   a.    
     As previously discussed, the label  30   a  enhances the visibility of the level of the photocurable material  14   a  in the vial  12   a  when the user is viewing the photocurable material  14   a  through the second portion  34   a  of label  30   a , or through the gap between end portions of the label  30   a . Advantageously, since the first section  32   a  also hinders transmission of actinic radiation, there is less likelihood than an undue amount of actinic radiation will reach the photocurable material  14   a.    
     Another embodiment of the invention is shown in FIGS. 4 and 5, wherein a packaged composition  10   b  includes a vial  12   b  and a photocurable material  14   b . Both the vial  12   b  and the photocurable material  14   b  are preferably identical to the vial  12  and photocurable material  14  previously described, except for the differences set out below. 
     The vial  12   b  includes a float or element  40   b  that is received in the chamber  18   b . The element  40   b  has a density less than the density of the photocurable material  14   b , and as a result floats in the photocurable material  14   b . The element  40   b  is visible through the side wall  16   b  that transmits light in a portion of the visible light spectrum, and thereby enhances the user&#39;s ability to determine the level or amount of photocurable material  14   b  in the chamber  18   b.    
     Prefqrably, the element  40   b  has dimensions along two axes that are smaller than the dimensions of the outlet  26   b  so that the element  40   b  can be inserted into the chamber  18   b  through the outlet  26   b  after the vial  12   b  is manufactured. As an example, if the chamber  18   b  of the vial  12   b  has an internal diameter of 0.64 inches (1.6 cm), the element  40   b  may have overall dimensions of 0.25×0.50 inches (6.4×13 mm) and a thickness of 0.06 inches (1.5 mm). As illustrated in FIG. 5, the element  40   b  preferably has an overall generally oval-shaped configuration in plan view. 
     Preferably, the element  40   b  has a thickness in the approximating range of 0.01-0.06 inches (0.25-1.5 mm). The flat shape and relatively small thickness of the element  40   b  helps the element return to a horizontal orientation after the vial  12  has been inverted and then returned to the upright vertical orientation as depicted in the Figures. Moreover, the flat shape of element  40   b  tends to cast a more distinct shadow than a float having, for example, a spherical shape, and as a result is relatively easy to see through the side wall  16   b . Further, the element  40   b  may have a central hole  42   b . The hole  42   b  improves fluid flow of the photocurable material  14   b  to the outlet  26   b  when the vial  12   b  is inverted during a dispensing operation. The element  40   b  is made of a material that is inert to the photocurable material  14   b . A suitable material for element  40   b  that is inert to many photocurable materials is polyethylene. The element  40   b  could be a liquid, a semi-liquid (gel or paste) or a solid material that is either hollow or not hollow, including materials which are foamed. 
     Another embodiment of the invention is depicted in FIG. 6, wherein a packaged composition  10   c  includes a vial  12   c  and a photocurable material  14   c , the latter of which is identical to the photocurable material  14  described previously. 
     The vial  12   c  has a generally oval-shaped overall configuration in plan view. A threaded neck portion  22   c  of the vial  12   c  is identical to the neck portion  22 , and may receive a cap of the type previously described. 
     The vial  12   c  has an upright side wall  16   c  which includes a first section  32   c  that is preferably covered or at least substantially covered with a coating. Preferably, the coating is opaque or at least substantially opaque to the passage of light in the visible spectrum as well as in the actinic spectrum. An example of a suitable coating is an ink that in applied by pad printing or screen printing technique and preceded by a flame treatment to insure good adhesion of the ink to the vial  12   c.    
     The upright side wall  16   c  includes a second portion  34   c  which lacks or substantially lacks the coating that is applied to the first section  32   c . As a consequence, the second section  36   c  transmits more light in the visible spectrum than the light transmitted to the first section  32   c , but still blocks actinic radiation by virtue of the colorant added to the polymeric material of the vial. 
     Additionally, the vial  12   c  includes a float or element  40   c  that is received in the chamber. The element  40   c  is somewhat similar to the element  40   b , but is longer in length in order to better match the shape of the chamber in plan view. The first section  32   c , the second section  34   c  and the element  40  help the user determine the level of photocurable material  14   c  in the chamber. 
     Those skilled in the art may recognize that a variety of alternatives are possible to the presently preferred embodiments described in detail above. For example, the shape of the vial may have another configuration, such as a configuration similar to squeezable tubes or squeezable containers of other configurations, and could be made of polymeric materials and colorants different from those materials and colorants previously set forth. Furthermore, the outlet could be open or covered with a sponge, brush, swab or other type of applicator. Accordingly, the scope of the invention should not be deemed limited by the specific descriptions mentioned above, but only by a fair reading of the claims that follow along with their equivalents.