I faced the brittle problem with my currently hot melt product. I am a book binding factory，can somebody tell me if it is normal situation or I chose the wrong hot melt items ?

The problem of insufficient strength such as embrittlement often occurs in winter, because hot melt adhesive suppliers usually fill the product with fillers to reduce costs, I suggest you contact a professional NANPAO salesperson to sell you the best product (Spine: HM- 718, margin: HM-619)