Writing instruments

Abstract

A writing instrument according to the present disclosure comprises a main body, a writing tip and a cap, wherein the cap is designed to be secured tightly on the main body such that the writing tip is covered by the cap. The cap comprises of an inner core and an outer layer, wherein a material of the outer layer is softer compared to a material of the inner core. With that, it is possible to design an air-tight (or almost air-tight) fitting cap for a writing instrument. With the softer outer layer of the cap, it is achieved that a user chewing on the cap has a reduced risk of damaging his/her teeth. In addition, although a membrane within the cap may still be present, such membrane is no longer necessary. The membrane may be an additional barrier contributing further to the air-tight effect of the cap that is present within the cap.

Claims

1. A writing instrument comprising a main body, a writing tip and a cap, wherein the cap includes a clip, wherein the cap is designed to be secured on the main body such that the writing tip is covered by the cap, wherein the cap comprises an inner core and an outer layer, wherein a material of the outer layer is softer, and exhibits a shore A hardness value that is lower, compared to a material of the inner core, and the outer layer extending over a radially outermost surface of the clip.

2. A writing instrument according to claim 1, further comprising at least one cartridge containing an ink, a colorant, or a mixture of ink or colorant and a solvent.

3. A writing instrument according to claim 2, wherein the inner core of the cap and the main body of the writing instrument are designed to form an air-tight or almost air-tight connection in order to encapsulate the writing tip, such that it prevents or reduces evaporation of the solvent, ink or colorant when volatile.

4. A writing instrument according to claim 2, wherein the cartridge has a ballpoint tip or a felt tip or a fountain tip.

5. A writing instrument according to claim 2, wherein the outer layer exhibits a same color as the ink or colorant of the writing instrument.

6. A writing instrument according to claim 1, wherein the inner core of the cap is made of a plastic material.

7. A writing instrument according to claim 6, wherein the inner core of the cap is made of a hard plastic material, which hard plastic material is a semicrystalline polymer or mixtures thereof.

8. A writing instrument according to claim 1, wherein the inner core of the cap is made of a material having a shrinkage rate upon cooling from 0.8% to 2.0%.

9. A writing instrument according to claim 1, wherein the inner core of the cap is made of polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and/or polypropylene (PP).

10. A writing instrument according to claim 1, wherein the outer layer covers the outer surface of the inner core completely or by at least 80% or 90%.

11. A writing instrument according to claim 1, wherein the outer layer is made of a material exhibiting shore A hardness value of less than 100 and the outer layer is made of a hypoallergenic and/or biocompatible material.

12. A writing instrument according to claim 11, wherein the outer layer is made of a material having shore A hardness 20A to 80A.

13. A writing instrument according to claim 12, wherein the outer layer is made of a material having shore A hardness 30A to 50A.

14. A writing instrument according to claim 1, wherein the outer layer is made of silicone rubber.

15. A writing instrument according to claim 1, wherein the outer layer further comprises one or more of an antimicrobial, antibacterial, antifungal, and an antiviral agent(s).

16. A writing instrument according to claim 1, wherein the cap is manufactured by using a two stage injection molding process, wherein in a first stage, plastic melt is injected in an inner core mold, and wherein in a second stage, liquid material is injected into a mold in which the inner core has been placed.

17. A writing instrument according to claim 1, wherein the outer layer is overmoulded.

18. The writing instrument according to claim 1, wherein the clip comprises an inner core and the inner core of clip comprises a harder material than the outer layer covering the clip.

19. The writing instrument of claim 18, wherein the clip extends away from the cap such that the inner core of the clip parallels the inner core of the cap without outer layer between the inner core of the clip and the inner core of the cap.

20. The writing instrument according to claim 1, wherein the radially inward surface of the clip is spaced apart from the remainder of the cap and is not in direct contact with the outer layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional details and features of the disclosure are described with reference to the following figures, in which

(2) FIG. 1a shows a first embodiment of a writing instrument according to the present disclosure;

(3) FIG. 1b shows another embodiment of a writing instrument according to the present disclosure;

(4) FIG. 2a shows an embodiment of a writing instrument with a cap comprised of two components;

(5) FIG. 2b shows an embodiment of a writing instrument with a cap including a clip, comprised of two components;

(6) FIG. 3a shows an enlarged embodiment of a cap comprised of two components;

(7) FIG. 3b shows an enlarged embodiment of a cap including a clip, comprised of two components;

DETAILED DESCRIPTION

(8) Embodiments of the writing instrument according to the disclosure will be described with reference to the figures as follows.

(9) FIG. 1a and FIG. 1b show a first embodiment of a writing instrument 1 comprising a main body, a writing tip 2 and a cap 3, wherein the cap 3 is designed to be secured tightly on the main body such that the writing tip 2 is covered by the cap 3. The cap may comprise a clip 4, to attach the writing instrument 1 to a suitable surface. The writing instrument 1 is further comprised of at least one cartridge 5 containing an ink, a colorant, or a mixture of ink or colorant and a solvent as shown in FIG. 1b. A ballpoint tip or a felt tip or a fountain tip or any type of tip such as pencil tip, graphene tip is forming the writing tip 2. The outer layer has the same color as the ink or colorant of the writing instrument 1, allowing an intuitive selection of the respective writing instrument.

(10) FIG. 2a shows an embodiment of the writing instrument 1 with a cap 3 made of two components. The cap 3 comprises of an inner core 3b and an outer layer 3a, wherein a material of the outer layer is softer compared to a material of the inner core. The inner core of the cap 3b and the main body of the writing instrument are designed to form an air-tight or almost air-tight connection in order to encapsulate the writing tip 2, such that it prevents or reduces evaporation of the solvent, ink or colorant when volatile, as well as prevent breakage of the writing tip 2. This ensures the writing tip 2 is protected from drying and the evaporation of potentially harmful substances is prevented. As a result, a membrane within the cap to ensure air-tight sealing is not necessary.

(11) FIG. 2b shows an embodiment of the writing instrument 1 with a cap 3 made of two components and a clip 4 to attach the writing instrument 1 to a desired surface. The clip 4 is also comprised of an inner core 3b and an outer core 3a. Given this, the risk of injuries is reduced compared to an exposed hard plastic clip.

(12) FIGS. 3a and 3b show an enlarged embodiment of a cap 3 comprised of two components. A clip 4 may be added as shown in FIG. 3b. The inner core 3b of the cap 3 is made of a rigid plastic material, in particular a hard plastic, providing tight tolerances to seal with the main body of the writing instrument. The use of a hard plastic material as the inner core material of the cap of the writing instrument contributes to maintaining its dimensions during the manufacturing process and the conditions applied, as well as leading to the production of an inner core that is dimensionally determined and solid allowing firm attachment and/or sealing of the main body of the writing instrument. The material of the inner core 3b of the cap 3 is made of polyamide (PA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and/or polypropylene (PP), and/or a semicrystalline polymer and/or mixtures thereof. The material of the inner core has a shrinkage rate upon cooling from 0.2% to 2.0%, more specifically 0.8% to 2.0%, more specifically 0.4% to 2.0%, more specifically 0.4% to 1.5%.

(13) The outer layer 3a is made of a hypoallergenic and/or biocompatible material, as often especially younger aged users tend to chew on the caps of writing instruments, exposing them to potentially harmful chemicals or risking injuries upon contact with the hard plastic inner core 3b. The outer layer 3a material is made of a material having shore A hardness 20A to 80A, more specifically 30A to 50A. The outer layer 3a is made of silicone rubber.

(14) The outer layer 3a further comprises an antimicrobial, antibacterial, antifungal and/or antiviral agent, to prevent microbial, fungal and/or viral growth and persistence in between uses. This ensures staining, bad odors and material degradation can be avoided or reduced, ensuring a longer lifetime of the product. The silicone rubber may be treated or coated with the respective antimicrobial, antibacterial, antifungal and/or antiviral agent(s), such as silver-based or polymer-based additives or coatings, more specifically silver-ion-based agents, copper-based agents or zinc pyrithione-based agents. With that it is possible to design a hygienic and tight-fitting cap 3, which even when chewed does not pose a health hazard. The soft material of the outer layer 3a covers the outer surface of the inner core 3b completely or by at least 80% or 90%, providing pleasant haptics and minimizing the risk of injuries in handling and even when the cap is being chewed on.

(15) The cap is manufactured by using a two-stage injection molding process, wherein in a first stage, plastic melt is injected in an inner core mold and solidified by cooling. In the second stage the inner core is overmoulded by injecting liquid silicon rubber in a mold, in which the inner core has been placed. The liquid silicon rubber is then cured by external stimuli, such as high temperature or UV light. In embodiments, the liquid silicone rubber may be a UV-curing LSR. In some embodiments, two separate machines/molds may also be used for the two-stage injection molding process, achieving similar result. In particular, the plastic melt of the first stage is injected in an inner core and subsequently the inner core is transferred in a separate machine/mold, where the liquid silicone rubber is injected on top of it.