text: exemplary embodiments of the present invention are now described with reference to the examples provided herein . although the following detailed description contains many specifics for purposes of illustration , a person of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention . accordingly , the following embodiments of the invention are set forth without any loss of generality to , and without imposing limitations upon , the claimed invention . the present invention utilizes acrylic dispersion technology as a unique polymer option for formulating glue sticks and the like . this technology provides improved overall adhesion , especially for non - wood or paper substrates , compared to pvp - based adhesives and modified pva - based adhesives . additionally , silane coupling agents are utilized to further improve adhesion to non - porous surfaces . such properties are obtained without sacrificing ease of lubricity or package stability , both of which are important for a properly functioning glue stick product . because the acrylic dispersions used in the present invention are low viscosity liquids , production time is reduced when compared to traditional pvp - based technology . pvp - based technology may require a product formulator to stabilize a color indicator ( e . g ., o - cresolphthalein or thymolphthalein ) with a sodium hydroxide solution to maintain a high ph value . the use of sodium hydroxide for acrylic glue stick products does not provide good color - disappearing ability after the glue stick is applied to paper and it dries . the color also degrades over time if a strong caustic solution is used . in one embodiment of the formula of the present invention , an organic amine ( e . g ., 2 - amino - 2 - methyl - 1 - propanol , a . k . a ., amp - 95 ) is included as a partial replacement for the caustic solution . this organic amine provides good color stabilization as the product ages , provides good color - disappearing properties after the glue stick is applied to paper , and formulation ph is maintained without degrading the included color indicators . organic amines are not currently used in the adhesives industry to stabilize pvp or modified - pva glue stick formulations . this approach is also believed to increase the ease of lubricity of the glue stick as it is applied to a substrate . having generally described this invention , a further understanding can be obtained by reference to certain specific examples detailed below , which are provided for purposes of illustration only and are not intended to be all inclusive or limiting unless otherwise specified . a first exemplary formulation provides a general - purpose acrylic glue stick ; a second exemplary formulation provides a color - changing / disappearing acrylic school glue stick ; and a third exemplary formulation provides an extra - strength glue stick . the first exemplary formula is prepared by adding the listed acrylic dispersions ( dsm coating resins , ceintuurbaan 5 , zwolle , the netherlands ), deionized water and antifoam - c into a mixer under agitation . after the mixing temperature is raised to 70 - 75 ° c ., sodium stearate is added and allowed to mix for 30 - 45 minutes . after mixing into a homogeneous blend , the caustic solution and propylene glycol are added and mixed for 10 - 15 minutes . the silane adhesion promoter ( e . g ., wetlink 78 ) is added and mixed under vacuum for 5 - 10 minutes . the molten glue is then filled into an empty glue stick container using a gravity feed method ( i . e ., flood filling ) which is easily performed due to the very low viscosity of the product at high temperatures . the second exemplary formula is prepared by adding the listed acrylic dispersions , deionized water and antifoam - c into a mixer under agitation . after the mixing temperature is raised to 70 - 75 ° c ., sodium stearate is added and allowed to mix for 30 - 45 minutes . after mixing into a homogeneous blend , the caustic solution and glycerin are added and mixed for 10 - 15 minutes . the o - cresolphthalein and thymolphthalein , after being wetted out with a small amount of glycerin which is withheld from the total formulation , are then added under agitation . after mixing for 5 minutes , the silane adhesion promoter ( e . g ., wetlink 78 ) is added and mixed 5 minutes . the amp - 95 is added to the mixture and allowed to mix 5 - 10 minutes under vacuum . the molten glue is then filled into an empty glue stick container . the third exemplary formula is prepared by adding the acrylic dispersions , deionized water and antifoam - c into a mixer under agitation . after the mixing temperature is raised to 70 - 75 ° c ., sodium stearate is added and allowed to mix for 30 - 45 minutes . after mixing into a homogeneous blend , the caustic solution and glycerin are added and mixed for 10 - 15 minutes . the silane adhesion promoter ( e . g ., wetlink 78 ) is added and mixed under vacuum for 5 - 10 minutes . if the formula described above does not flow easily , a positive pressure filling device ( i . e ., a press ) may be utilized to fill the product into an appropriate glue stick container . essentially , the present invention provides glue stick formulas based on acrylic dispersion technology , which is not typically used to formulate consumer glue stick products , as well as a novel means for stabilizing the color - disappearing acrylic glue stick , and a novel means of filling highly viscous glue sticks . while the present invention has been illustrated by the description of exemplary embodiments thereof , and while the embodiments have been described in certain detail , it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail . additional advantages and modifications will readily appear to those skilled in the art . therefore , the invention in its broader aspects is not limited to any of the specific details , representative devices and methods , and / or illustrative examples shown and described . accordingly , departures may be made from such details without departing from the spirit or scope of the applicant &# 39 ; s general inventive concept .